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Check that file exists

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Task
Check that file exists
You are encouraged to solve this task according to the task description, using any language you may know.
Task

Verify that a file called     input.txt     and   a directory called     docs     exist.


This should be done twice:  

  •   once for the current working directory,   and
  •   once for a file and a directory in the filesystem root.


Optional criteria (May 2015):   verify it works with:

  •   zero-length files
  •   an unusual filename:   `Abdu'l-Bahá.txt



11l

Translation of: Python
fs:is_file(‘input.txt’)
fs:is_file(‘/input.txt’)
fs:is_dir(‘docs’)
fs:is_dir(‘/docs’)

AArch64 Assembly

Works with: as version Raspberry Pi 3B version Buster 64 bits
/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program verifFic64.s   */

/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ CHDIR,   49
.equ AT_FDCWD,    -100

/*******************************************/
/* Initialized data                        */
/*******************************************/
.data
szMessFound1:     .asciz "File 1 found.\n"
szMessFound2:     .asciz "File 2 found.\n"
szMessNotFound1:  .asciz "File 1 not found.\n"
szMessNotFound2:  .asciz "File 2 not found.\n"
szMessDir2:       .asciz "File 2 is a directory.\n"
szMessNotAuth2:   .asciz "File 2 permission denied.\n"
szCarriageReturn: .asciz "\n"
 
/* areas strings  */
szPath2:          .asciz "/"
szFicName1:       .asciz "test1.txt"
szFicName2:       .asciz "root"
 
/*******************************************/
/* UnInitialized data                      */
/*******************************************/
.bss 
/*******************************************/
/*  code section                           */
/*******************************************/
.text
.global main 
main:                        // entry of program

    /*************************************
     open file 1
    ************************************/
    mov x0,AT_FDCWD          // current directory
    ldr x1,qAdrszFicName1    // file name
    mov x2,#O_RDWR           // flags
    mov x3,#0                // mode 
    mov x8, #OPEN            // call system OPEN 
    svc 0 
    cmp x0,#0                // error ?
    ble 1f
    mov x1,x0                // FD
    ldr x0,qAdrszMessFound1
    bl affichageMess
                             // close file
    mov x0,x1                // Fd 
    mov x8, #CLOSE 
    svc 0 
    b 2f
1:
    ldr x0,qAdrszMessNotFound1
    bl affichageMess
2:
    /*************************************
     open file 2
    ************************************/
    ldr x0,qAdrszPath2
    mov x8,CHDIR            // call system change directory
    svc 0 
    mov x0,AT_FDCWD         // current directory
    ldr x1,qAdrszFicName2   // file name 
    mov x2,O_RDWR           //  flags
    mov x3,0                // mode 
    mov x8,OPEN             // call system OPEN 
    svc 0 
    cmp x0,-21              // is a directory ?
    beq 4f
    cmp x0,0                // error ? 
    ble 3f
    mov x1,x0               // FD
    ldr x0,qAdrszMessFound2
    bl affichageMess
                            // close file
    mov x0,x1               // Fd 
    mov x8, #CLOSE 
    svc 0 
    b 100f
3:
    ldr x0,qAdrszMessNotFound2
    bl affichageMess
    b 100f
4:
    ldr x0,qAdrszMessDir2
    bl affichageMess
100:                           // standard end of the program
    mov x0,0                   // return code
    mov x8,EXIT                // request to exit program
    svc 0                      // perform the system call
qAdrszFicName1:            .quad szFicName1
qAdrszFicName2:            .quad szFicName2
qAdrszMessFound1:          .quad szMessFound1
qAdrszMessFound2:          .quad szMessFound2
qAdrszMessNotFound1:       .quad szMessNotFound1
qAdrszMessNotFound2:       .quad szMessNotFound2
qAdrszMessNotAuth2:        .quad szMessNotAuth2
qAdrszPath2:               .quad szPath2
qAdrszMessDir2:            .quad szMessDir2
/********************************************************/
/*        File Include fonctions                        */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"

Action!

BYTE lastError

PROC MyError(BYTE errCode)
  lastError=errCode
RETURN

BYTE FUNC FileExists(CHAR ARRAY fname)
  DEFINE PTR="CARD"
  PTR old
  BYTE dev=[1]

  lastError=0
  old=Error
  Error=MyError ;replace error handling to capture I/O error

  Close(dev)
  Open(dev,fname,4)
  Close(dev)

  Error=old ;restore the original error handling

  IF lastError=0 THEN
    RETURN (1)
  FI
RETURN (0)

PROC Test(CHAR ARRAY fname)
  BYTE exists

  exists=FileExists(fname)
  IF exists THEN
    PrintF("File ""%S"" exists.%E",fname)
  ELSE
    PrintF("File ""%S"" does not exist.%E",fname)
  FI
RETURN

PROC Main()
  Test("D:INPUT.TXT")
  Test("D:DOS.SYS")
RETURN
Output:

Screenshot from Atari 8-bit computer

File "D:INPUT.TXT" does not exist.
File "D:DOS.SYS" exists.

Ada

This example should work with any Ada 95 compiler.

with Ada.Text_IO; use Ada.Text_IO;

procedure File_Exists is
   function Does_File_Exist (Name : String) return Boolean is
      The_File : Ada.Text_IO.File_Type;
   begin
      Open (The_File, In_File, Name);
      Close (The_File);
      return True;
   exception
      when Name_Error =>
         return False;
   end Does_File_Exist;
begin
   Put_Line (Boolean'Image (Does_File_Exist ("input.txt" )));
   Put_Line (Boolean'Image (Does_File_Exist ("\input.txt")));
end File_Exists;

This example should work with any Ada 2005 compiler.

with Ada.Text_IO; use Ada.Text_IO;
with Ada.Directories; use Ada.Directories;

procedure File_Exists is
   procedure Print_File_Exist (Name : String) is
   begin
      Put_Line ("Does " & Name & " exist? " &
                  Boolean'Image (Exists (Name)));
   end Print_File_Exist;
   procedure Print_Dir_Exist (Name : String) is
   begin
      Put_Line ("Does directory " & Name & " exist? " &
                  Boolean'Image (Exists (Name) and then Kind (Name) = Directory));
   end Print_Dir_Exist;
begin
   Print_File_Exist ("input.txt" );
   Print_File_Exist ("/input.txt");
   Print_Dir_Exist ("docs");
   Print_Dir_Exist ("/docs");
end File_Exists;

Aikido

The stat function returns a System.Stat object for an existing file or directory, or null if it can't be found.

function exists (filename) {
    return stat (filename) != null
}

exists ("input.txt")
exists ("/input.txt")
exists ("docs")
exists ("/docs")

ALGOL 68

Works with: ALGOL 68G version Any - tested with release 2.8.3.win32

Uses the Algol 68G specific "file is directory" procedure to test for the existence of directories.

# Check files and directories exist                               #

# check a file exists by attempting to open it for input          #
# returns TRUE if the file exists, FALSE otherwise                #
PROC file exists = ( STRING file name )BOOL:
    IF  FILE f;
        open( f, file name, stand in channel ) = 0
    THEN
        # file opened OK so must exist                            #
        close( f );
        TRUE
    ELSE
        # file cannot be opened - assume it does not exist        #
        FALSE
    FI # file exists # ;

# print a suitable messages if the specified file exists          #
PROC test file exists = ( STRING name )VOID:
    print( ( "file: "
           , name
           , IF file exists( name ) THEN " does" ELSE " does not" FI
           , " exist"
           , newline
           )
         );
# print a suitable messages if the specified directory exists     #
PROC test directory exists = ( STRING name )VOID:
    print( ( "dir:  "
           , name
           , IF file is directory( name ) THEN " does" ELSE " does not" FI
           , " exist"
           , newline
           )
         );

# test the flies and directories mentioned in the task exist or not #
test file exists( "input.txt" );
test file exists( "\input.txt");
test directory exists( "docs" );
test directory exists( "\docs" )

Amazing Hopper

Version: hopper-FLOW!:

#include <flow.h>

DEF-MAIN(argv, argc)
   WHEN( IS-FILE?("hopper") ){
      MEM("File \"hopper\" exist!\n")
   }
   WHEN( IS-DIR?("fl") ){
      MEM("Directory \"fl\" exist!\n")
   }
   IF( IS-DIR?("noExisDir"), "Directory \"noExistDir\" exist!\n", \
                             "Directory \"noExistDir\" does NOT exist!\n" )
   //"arch mañoso bacán.txt" text-file created

   STR-TO-UTF8("File \"arch mañoso bacán.txt\" ")
   IF( IS-FILE?( STR-TO-UTF8("arch mañoso bacán.txt") ), "exist!\n", "NOT exist!\n")

   PRNL
END
Output:
$ hopper existFile.flw
File "hopper" exist!
Directory "fl" exist!
Directory "noExistDir" does NOT exist!
File "arch mañoso bacán.txt" exist!
$

APL

      h  ⎕fio['fopen'] 'input.txt'
      h
7
      ⎕fio['fstat'] h
66311 803134 33188 1 1000 1000 0 11634 4096 24 1642047105 1642047105 1642047105
      ⎕fio['fclose'] h
0
      h  ⎕fio['fopen'] 'docs/'    
      h
7
      ⎕fio['fstat'] h
66311 3296858 16877 2 1000 1000 0 4096 4096 8 1642047108 1642047108 1642047108
      ⎕fio['fclose'] h
0
      h  ⎕fio['fopen'] 'does_not_exist.txt'
      h
¯1

AppleScript

Translation of: JavaScript

(macOS JavaScript for Automation)

use framework "Foundation" -- YOSEMITE OS X onwards
use scripting additions

on run
    setCurrentDirectory("~/Desktop")
    
    ap({doesFileExist, doesDirectoryExist}, ¬
        {"input.txt", "/input.txt", "docs", "/docs"})
    
    --> {true, true, true, true, false, false, true, true}
    
    -- The first four booleans are returned by `doesFileExist`.
    
    -- The last four are returned by `doesDirectoryExist`,
    -- which yields false for simple files, and true for directories.
end run

-- GENERIC SYSTEM DIRECTORY FUNCTIONS -----------------------------------------

-- doesDirectoryExist :: String -> Bool
on doesDirectoryExist(strPath)
    set ca to current application
    set oPath to (ca's NSString's stringWithString:strPath)'s ¬
        stringByStandardizingPath
    set {bln, int} to (ca's NSFileManager's defaultManager()'s ¬
        fileExistsAtPath:oPath isDirectory:(reference))
    bln and (int = 1)
end doesDirectoryExist

-- doesFileExist :: String -> Bool
on doesFileExist(strPath)
    set ca to current application
    set oPath to (ca's NSString's stringWithString:strPath)'s ¬
        stringByStandardizingPath
    ca's NSFileManager's defaultManager()'s fileExistsAtPath:oPath
end doesFileExist

-- getCurrentDirectory :: String
on getCurrentDirectory()
    set ca to current application
    ca's NSFileManager's defaultManager()'s currentDirectoryPath as string
end getCurrentDirectory

-- getFinderDirectory :: String
on getFinderDirectory()
    tell application "Finder" to POSIX path of (insertion location as alias)
end getFinderDirectory

-- getHomeDirectory :: String
on getHomeDirectory()
    (current application's NSHomeDirectory() as string)
end getHomeDirectory

-- setCurrentDirectory :: String -> IO ()
on setCurrentDirectory(strPath)
    if doesDirectoryExist(strPath) then
        set ca to current application
        set oPath to (ca's NSString's stringWithString:strPath)'s ¬
            stringByStandardizingPath
        ca's NSFileManager's defaultManager()'s ¬
            changeCurrentDirectoryPath:oPath
    end if
end setCurrentDirectory


-- GENERIC HIGHER ORDER FUNCTIONS FOR THE TEST --------------------------------

-- A list of functions applied to a list of arguments
-- (<*> | ap) :: [(a -> b)] -> [a] -> [b]
on ap(fs, xs)
    set {intFs, intXs} to {length of fs, length of xs}
    set lst to {}
    repeat with i from 1 to intFs
        tell mReturn(item i of fs)
            repeat with j from 1 to intXs
                set end of lst to |λ|(contents of (item j of xs))
            end repeat
        end tell
    end repeat
    return lst
end ap

-- Lift 2nd class handler function into 1st class script wrapper 
-- mReturn :: Handler -> Script
on mReturn(f)
    if class of f is script then
        f
    else
        script
            property |λ| : f
        end script
    end if
end mReturn
Output:

The first four booleans are returned by `doesFileExist`.

The last four are returned by `doesDirectoryExist`, which yields false for simple files, and true for directories.

{true, true, true, true, false, false, true, true}

Applesoft BASIC

The error code for FILE NOT FOUND is 6.

100 F$ = "THAT FILE"
110 T$(0) = "DOES NOT EXIST."
120 T$(1) = "EXISTS."
130 GOSUB 200"FILE EXISTS?
140 PRINT F$; " "; T$(E)
150 END

200 REM FILE EXISTS?
210 REM TRY
220    ON ERR GOTO 300"CATCH
230    PRINT CHR$(4); "VERIFY "; F$
240    POKE 216, 0 : REM ONERR OFF
250    E = 1
260    GOTO 350"END TRY
300 REM CATCH
310    E = PEEK(222) <> 6
320    POKE 216, 0 : REM ONERR OFF
330    IF E THEN RESUME : REM THROW
340    CALL  - 3288 : REM RECOVER
350 REM END TRY
360 RETURN

ARM Assembly

Works with: as version Raspberry Pi
/* ARM assembly Raspberry PI  */
/*  program verifFic.s   */

/* Constantes    */
.equ STDOUT, 1     @ Linux output console
.equ EXIT,   1     @ Linux syscall
.equ WRITE,  4     @ Linux syscall
.equ OPEN,   5     @ Linux syscall
.equ CLOSE, 6     @ Linux syscall

.equ O_RDWR,	0x0002		/* open for reading and writing */

/*******************************************/
/* Fichier des macros                       */
/********************************************/
.include "../../ficmacros.s"

/* Initialized data */
.data
szMessFound1:     .asciz "File 1 found.\n"
szMessFound2:     .asciz "File 2 found.\n"
szMessNotFound1: .asciz "File 1 not found.\n"
szMessNotFound2: .asciz "File 2 not found.\n"
szMessNotAuth2:   .asciz "File 2 permission denied.\n"
szCarriageReturn: .asciz "\n"

/* areas strings  */
szFicName1:  .asciz "test1.txt"
szFicName2:  .asciz "/debian-binary"


/* UnInitialized data */
.bss 

/*  code section */
.text
.global main 
main:                /* entry of program  */
    push {fp,lr}    /* saves 2 registers */

    /*************************************
     open file 1
    ************************************/
    ldr r0,iAdrszFicName1    @ file name
    mov r1,#O_RDWR             @ flags    
    mov r2,#0                    @ mode 
    mov r7, #OPEN               @ call system OPEN 
    swi 0 
    cmp r0,#0    @ error ?
    ble 1f
    mov r1,r0    @ FD
    ldr r0,iAdrszMessFound1
    bl affichageMess
    @ close file
    mov r0,r1   @ Fd 
    mov r7, #CLOSE 
    swi 0 
    b 2f
1:
    ldr r0,iAdrszMessNotFound1
    bl affichageMess
2:
    /*************************************
     open file 2
    ************************************/
    ldr r0,iAdrszFicName2    @ file name 
    mov r1,#O_RDWR   @  flags    
    mov r2,#0         @ mode 
    mov r7, #OPEN    @ call system OPEN 
    swi 0 
    vidregtit verif
    cmp r0,#-13    @ permission denied 
    beq 4f
    cmp r0,#0    @ error ? 
    ble 3f
    mov r1,r0    @ FD
    ldr r0,iAdrszMessFound2
    bl affichageMess
    @ close file
    mov r0,r1   @ Fd 
    mov r7, #CLOSE 
    swi 0 
    b 100f
3:
    ldr r0,iAdrszMessNotFound2
    bl affichageMess
    b 100f
4:
    ldr r0,iAdrszMessNotAuth2
    bl affichageMess
100:   /* standard end of the program */
    mov r0, #0                  @ return code
    pop {fp,lr}                 @restaur 2 registers
    mov r7, #EXIT              @ request to exit program
    swi 0                       @ perform the system call
iAdrszFicName1:			.int szFicName1
iAdrszFicName2:			.int szFicName2
iAdrszMessFound1:		.int szMessFound1
iAdrszMessFound2:		.int szMessFound2
iAdrszMessNotFound1: 	.int szMessNotFound1
iAdrszMessNotFound2: 	.int szMessNotFound2
iAdrszMessNotAuth2:	.int szMessNotAuth2
/******************************************************************/
/*     display text with size calculation                         */ 
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
    push {fp,lr}    			/* save  registres */ 
    push {r0,r1,r2,r7}    		/* save others registers */
    mov r2,#0   				/* counter length */
1:      	/* loop length calculation */
    ldrb r1,[r0,r2]  			/* read octet start position + index */
    cmp r1,#0       			/* if 0 its over */
    addne r2,r2,#1   			/* else add 1 in the length */
    bne 1b          			/* and loop */
                                /* so here r2 contains the length of the message */
    mov r1,r0        			/* address message in r1 */
    mov r0,#STDOUT      		/* code to write to the standard output Linux */
    mov r7, #WRITE             /* code call system "write" */
    swi #0                      /* call systeme */
    pop {r0,r1,r2,r7}     		/* restaur others registers */
    pop {fp,lr}    				/* restaur des  2 registres */ 
    bx lr	        			/* return  */

Arturo

checkIfExists: function [fpath][
    (or? exists? fpath
         exists? .directory fpath)? -> print [fpath "exists"]
                                    -> print [fpath "doesn't exist"]
]
 
checkIfExists "input.txt"
checkIfExists "docs"
 
checkIfExists "/input.txt"
checkIfExists "/docs"

AutoHotkey

AutoHotkey’s FileExist() function returns an attribute string (a subset of "RASHNDOCT") if a matching file or directory is found. The attribute string must be parsed for the letter D to determine whether the match is a directory or file.

Another option is AutoHotkey's IfExist/IfNotExist command

; FileExist() function examples
ShowFileExist("input.txt")
ShowFileExist("\input.txt")
ShowFolderExist("docs")
ShowFolderExist("\docs")

; IfExist/IfNotExist command examples (from documentation)
IfExist, D:\
  MsgBox, The drive exists.
IfExist, D:\Docs\*.txt
  MsgBox, At least one .txt file exists.
IfNotExist, C:\Temp\FlagFile.txt
  MsgBox, The target file does not exist.

Return

ShowFileExist(file)
{
  If (FileExist(file) && !InStr(FileExist(file), "D"))
    MsgBox, file: %file% exists.
  Else
    MsgBox, file: %file% does NOT exist.
  Return
}

ShowFolderExist(folder)
{
  If InStr(FileExist(folder), "D")
    MsgBox, folder: %folder% exists.
  Else
    MsgBox, folder: %folder% does NOT exist.
  Return
}

AWK

Works with: gawk
@load "filefuncs"

function exists(name    ,fd) {
    if ( stat(name, fd) == -1)
      print name " doesn't exist"
    else
      print name " exists"
}
BEGIN {
    exists("input.txt")
    exists("/input.txt")
    exists("docs")
    exists("/docs")
}

Portable getline method. Also works in a Windows environment.

#
# Check if file or directory exists, even 0-length file.
#   Return 0 if not exist, 1 if exist
#
function exists(file    ,line, msg)
{
        if ( (getline line < file) == -1 )
        {
                # "Permission denied" is for MS-Windows
                msg = (ERRNO ~ /Permission denied/ || ERRNO ~ /a directory/) ? 1 : 0
                close(file)
                return msg
        }
        else {
                close(file)
                return 1
        }
}
BEGIN {
    exists("input.txt")
    exists("\\input.txt")
    exists("docs")
    exists("\\docs")
    exit(0)
}
Works with: gawk

Check file(s) existence

gawk 'BEGINFILE{if (ERRNO) {print "Not exist."; nextfile} else {print "Exist."; nextfile}}' input.txt input-missing.txt

Axe

If GetCalc("appvINPUT")
 Disp "EXISTS",i
Else
 Disp "DOES NOT EXIST",i
End

BASIC

Works with: QBasic
ON ERROR GOTO ohNo
f$ = "input.txt"
GOSUB opener
f$ = "\input.txt"
GOSUB opener

'can't directly check for directories,
'but can check for the NUL device in the desired dir
f$ = "docs\nul"
GOSUB opener
f$ = "\docs\nul"
GOSUB opener
END

opener:
    e$ = " found"
    OPEN f$ FOR INPUT AS 1
    PRINT f$; e$
    CLOSE
    RETURN

ohNo:
    IF (53 = ERR) OR (76 = ERR) THEN
        e$ = " not" + e$
    ELSE
        e$ = "Unknown error"
    END IF
    RESUME NEXT

You can also check for a directory by trying to enter it.

ON ERROR GOTO ohNo
d$ = "docs"
CHDIR d$
d$ = "\docs"
CHDIR d$
END

ohNo:
    IF 76 = ERR THEN
        PRINT d$; " not found"
    ELSE
        PRINT "Unknown error"
    END IF
    RESUME NEXT
Works with: QuickBasic version 7.1
Works with: PowerBASIC for DOS

Later versions of MS-compatible BASICs include the DIR$ keyword, which makes this pretty trivial.

f$ = "input.txt"
GOSUB opener
f$ = "\input.txt"
GOSUB opener

'can't directly check for directories,
'but can check for the NUL device in the desired dir
f$ = "docs\nul"
GOSUB opener
f$ = "\docs\nul"
GOSUB opener
END

opener:
    d$ = DIR$(f$)
    IF LEN(d$) THEN
        PRINT f$; " found"
    ELSE
        PRINT f$; " not found"
    END IF
    RETURN

BaCon

' File exists
f$ = "input.txt"
d$ = "docs"
IF FILEEXISTS(f$) THEN PRINT f$, " exists"
IF FILEEXISTS(d$) AND FILETYPE(d$) = 2 THEN PRINT d$, " directory exists"

f$ = "/" & f$
d$ = "/" & d$
PRINT f$, IIF$(FILEEXISTS(f$), " exists", " does not exist")
PRINT d$, IIF$(FILEEXISTS(d$) AND FILETYPE(d$) = 2, " is", " is not"), " a directory"

f$ = "empty.bac"
PRINT f$, IIF$(FILEEXISTS(f$), " exists", " does not exist")

f$ = "`Abdu'l-Bahá.txt"
PRINT f$, IIF$(FILEEXISTS(f$), " exists", " does not exist")
Output:
prompt$ ./fileexits
/input.txt does not exist
/docs is not a directory
empty.bac exists
`Abdu'l-Bahá.txt does not exist


Commodore BASIC

Try a file, then check the error status of the disk drive. Error code 62 is the "File not found" error. The trick is to open the file without specifying the file type (PRG, SEQ, REL, etc.) and the Read/Write mode in the OPEN statement, otherwise you may end up with error code 64 "File Type Mismatch".

10 REM CHECK FILE EXISTS
15 ER=0:EM$="":MSG$="FILE EXISTS."
20 PRINT CHR$(147);:REM CLEAR SCREEN
30 FI$="":INPUT "ENTER FILENAME TO CHECK";FI$:PRINT
35 IF FI$="" THEN PRINT "ABORTED.":END
40 OPEN 8,8,8,FI$
50 GOSUB 1000:REM FETCH ERROR STATUS FROM DRIVE: 0=OK, 62=FILE NOT FOUND
55 REM COMPARE ERROR NUMBER
60 IF ER<>0 THEN MSG$="I/O ERROR:"+STR$(ER)+" "+EM$
70 IF ER=62 THEN MSG$="'"+FI$+"' IS NOT HERE."
80 REM DO THINGS WITH FILE...
100 CLOSE 8
110 PRINT MSG$
120 PRINT:GOTO 30:REM REPEAT UNTIL EMPTY FILENAME IS ENTERED
1000 REM CHECK ERROR CHANNEL FOR STATUS OF LAST DISK OPERATION
1010 OPEN 15,8,15
1015 REM GET ERROR CODE, ERROR MESSAGE, TRACK, SECTOR
1020 INPUT#15,ER,EM$,T,S
1030 CLOSE 15
1040 RETURN
Output:
ENTER FILENAME TO CHECK? INDEX.TXT

FILE EXISTS.

ENTER FILENAME TO CHECK? NOFILE.DOC

'NOFILE.DOC' IS NOT HERE.

SmallBASIC

if(isdir("docs"))        then print "directory docs exist"
if(isdir("/docs"))       then print "directory /docs exist"
if(isfile("input.txt"))  then print "file input.txt exist"
if(isfile("/input.txt")) then print "file /input.txt exist"


BASIC256

subroutine opener (filename$)
    if exists(filename$) then
	print filename$; " exists"
    else
	print filename$; " does not exists"
    end if
end subroutine

call opener ("input.txt")
call opener ("\input.txt")
call opener ("docs\nul")
call opener ("\docs\nul")
call opener ("empty.kbs")
call opener ("`Abdu'l-Bahá.txt"))
end

Batch File

if exist input.txt echo The following file called input.txt exists.
if exist \input.txt echo The following file called \input.txt exists.
if exist docs echo The following directory called docs exists.
if exist \docs\ echo The following directory called \docs\ exists.

BBC BASIC

      test% = OPENIN("input.txt")
      IF test% THEN
        CLOSE #test%
        PRINT "File input.txt exists"
      ENDIF
      
      test% = OPENIN("\input.txt")
      IF test% THEN
        CLOSE #test%
        PRINT "File \input.txt exists"
      ENDIF
      
      test% = OPENIN("docs\NUL")
      IF test% THEN
        CLOSE #test%
        PRINT "Directory docs exists"
      ENDIF
      
      test% = OPENIN("\docs\NUL")
      IF test% THEN
        CLOSE #test%
        PRINT "Directory \docs exists"
      ENDIF

BQN

Works In: CBQN

Takes filename as a command line argument, tells whether it exists.

fname  args
•Out fname" Does not exist"" Exists"˜•File.exists fname

C

Library: POSIX
#include <sys/types.h> 
#include <sys/stat.h>
#include <stdio.h>
#include <unistd.h>

/* Check for regular file. */
int check_reg(const char *path) {
	struct stat sb;
	return stat(path, &sb) == 0 && S_ISREG(sb.st_mode);
}

/* Check for directory. */
int check_dir(const char *path) {
	struct stat sb;
	return stat(path, &sb) == 0 && S_ISDIR(sb.st_mode);
}

int main() {
	printf("input.txt is a regular file? %s\n",
	    check_reg("input.txt") ? "yes" : "no");
	printf("docs is a directory? %s\n",
	    check_dir("docs") ? "yes" : "no");
	printf("/input.txt is a regular file? %s\n",
	    check_reg("/input.txt") ? "yes" : "no");
	printf("/docs is a directory? %s\n",
	    check_dir("/docs") ? "yes" : "no");
	return 0;
}
Library: Gadget
#include <gadget/gadget.h>

LIB_GADGET_START

/* input.txt = check_file.c 
   docs = tests */

Main
    Print "tests/check_file.c is a regular file? %s\n", Exist_file("tests/check_file.c") ? "yes" : "no";
    Print "tests is a directory? %s\n",                 Exist_dir("tests") ? "yes" : "no";
    Print "some.txt is a regular file? %s\n",           Exist_file("some.txt") ? "yes" : "no";
    Print "/tests is a directory? %s\n",                Exist_dir("/tests") ? "yes" : "no";
End
Output:
tests/check_file.c is a regular file? yes
tests is a directory? yes
some.txt is a regular file? no
/tests is a directory? no

C#

using System.IO;

Console.WriteLine(File.Exists("input.txt"));
Console.WriteLine(File.Exists("/input.txt"));
Console.WriteLine(Directory.Exists("docs"));
Console.WriteLine(Directory.Exists("/docs"));

C++

Library: boost
#include "boost/filesystem.hpp"
#include <string>
#include <iostream>

void testfile(std::string name)
{
  boost::filesystem::path file(name);
  if (exists(file))
  {
    if (is_directory(file))
      std::cout << name << " is a directory.\n";
    else
      std::cout << name << " is a non-directory file.\n";
  }
  else
    std::cout << name << " does not exist.\n";
}

int main()
{
  testfile("input.txt");
  testfile("docs");
  testfile("/input.txt");
  testfile("/docs");
}

Using C++ 17

C++ 17 contains a Filesystem library which significantly improves operations with files.

#include <iostream>
#include <filesystem>

void file_exists(const std::filesystem::path& path) {
    std::cout << path;
    if (  std::filesystem::exists(path) ) {
    	if ( std::filesystem::is_directory(path) ) {
    		std::cout << " is a directory" << std::endl;
    	} else {
    		std::cout << " exists with a file size of " << std::filesystem::file_size(path) << " bytes." << std::endl;
    	}
    } else {
        std::cout << " does not exist" << std::endl;
    }
}

int main() {
	file_exists("input.txt");
	file_exists("zero_length.txt");
	file_exists("docs/input.txt");
	file_exists("docs/zero_length.txt");
}
Output:

"input.txt" exists with a file size of 11 bytes.

"zero_length.txt" exists with a file size of 0 bytes.

"docs/input.txt" exists with a file size of 11 bytes.

"docs/zero_length.txt" exists with a file size of 0 bytes.

Clojure

(dorun (map #(.exists (clojure.java.io/as-file %)) '("/input.txt" "/docs" "./input.txt" "./docs")))

COBOL

Works with: GnuCOBOL

and other compilers with this system call extension

       identification division.
       program-id. check-file-exist.

       environment division.
       configuration section.
       repository.
           function all intrinsic.

       data division.
       working-storage section.
       01 skip                 pic 9 value 2.
       01 file-name.
          05 value "/output.txt".
       01 dir-name.
          05 value "/docs/".
       01 unusual-name.
          05 value "Abdu'l-Bahá.txt".

       01 test-name            pic x(256).

       01 file-handle          usage binary-long.
       01 file-info.
          05 file-size         pic x(8) comp-x.
          05 file-date.
             10 file-day       pic x comp-x.
             10 file-month     pic x comp-x.
             10 file-year      pic xx comp-x.
          05 file-time.
             10 file-hours     pic x comp-x.
             10 file-minutes   pic x comp-x.
             10 file-seconds   pic x comp-x.
             10 file-hundredths  pic x comp-x. 

       procedure division.
       files-main.

      *> check in current working dir
       move file-name(skip:) to test-name
       perform check-file

       move dir-name(skip:) to test-name
       perform check-file

       move unusual-name to test-name
       perform check-file

      *> check in root dir
       move 1 to skip
       move file-name(skip:) to test-name
       perform check-file

       move dir-name(skip:) to test-name
       perform check-file

       goback.

       check-file.
       call "CBL_CHECK_FILE_EXIST" using test-name file-info
       if return-code equal zero then
           display test-name(1:32) ": size " file-size ", "
                   file-year "-" file-month "-" file-day space
                   file-hours ":" file-minutes ":" file-seconds "."
                   file-hundredths
       else
           display "error: CBL_CHECK_FILE_EXIST " return-code space
                   trim(test-name)
       end-if
       .

       end program check-file-exist.
Output:
prompt$ cobc -xj check-file-exists.cob
output.txt                      : size 000000000000000000, 2016-06-01 09:27:14.00
docs/                           : size 000000000000004096, 2016-06-01 09:27:14.00
error: CBL_CHECK_FILE_EXIST +000000035 Abdu'l-Bahá.txt
error: CBL_CHECK_FILE_EXIST +000000035 /output.txt
error: CBL_CHECK_FILE_EXIST +000000035 /docs/
prompt$ echo -n >Abdu\'l-Bahá.txt
prompt$ cobc -xj check-file-exists.cob
output.txt                      : size 000000000000000000, 2016-06-01 09:27:14.00
docs/                           : size 000000000000004096, 2016-06-01 09:27:14.00
Abdu'l-Bahá.txt                 : size 000000000000000000, 2016-06-01 09:33:35.00
error: CBL_CHECK_FILE_EXIST +000000035 /output.txt
error: CBL_CHECK_FILE_EXIST +000000035 /docs/

Errors due to file and dir not existing in root directory for this test pass

CoffeeScript

Works with: Node.js
fs = require 'fs'
path = require 'path'

root = path.resolve '/'
current_dir = __dirname
filename = 'input.txt'
dirname = 'docs'

local_file = path.join current_dir, filename
local_dir = path.join current_dir, dirname

root_file = path.join root, filename
root_dir = path.join root, dirname

for p in [ local_file, local_dir, root_file, root_dir ] then do ( p ) ->
    fs.exists p, ( p_exists ) ->
        unless p_exists
            console.log "#{ p } does not exist."
        else then fs.stat p, ( error, stat ) ->
            console.log "#{ p } exists and is a #{ if stat.isFile() then 'file' else then 'directory' }."

Common Lisp

probe-file returns nil if a file does not exist. directory returns nil if there are no files in a specified directory.

(if (probe-file (make-pathname :name "input.txt"))
    (print "rel file exists"))
(if (probe-file (make-pathname :directory '(:absolute "") :name "input.txt"))
    (print "abs file exists"))

(if (directory (make-pathname :directory '(:relative "docs")))
    (print "rel directory exists")
    (print "rel directory is not known to exist"))
(if (directory (make-pathname :directory '(:absolute "docs")))
    (print "abs directory exists")
    (print "abs directory is not known to exist"))

There is no standardized way to determine if an empty directory exists, as Common Lisp dates from before the notion of directories as a type of file was near-universal. CL-FAD provides many of the therefore-missing capabilities in a cross-implementation library.

Library: CL-FAD
(if (cl-fad:directory-exists-p (make-pathname :directory '(:relative "docs")))
    (print "rel directory exists")
    (print "rel directory does not exist"))

Crystal

def check_file(filename : String)
  if File.directory?(filename)
    puts "#{filename} is a directory"
  elsif File.exists?(filename)
    puts "#{filename} is a file"
  else
    puts "#{filename} does not exist"
  end
end

check_file("input.txt")
check_file("docs")
check_file("/input.txt")
check_file("/docs")

D

import std.stdio, std.file, std.path;

void verify(in string name) {
    if (name.exists())
        writeln("'", name, "' exists");
    else
        writeln("'", name, "' doesn't exist");
}

void main() {
    // check in current working dir
    verify("input.txt");
    verify("docs");

    // check in root
    verify(dirSeparator ~ "input.txt");
    verify(dirSeparator ~ "docs");
}
Output:
'input.txt' doesn't exist
'docs' doesn't exist
'\input.txt' doesn't exist
'\docs' doesn't exist

DBL

;
;       Check file and directory exists for DBL version 4 by Dario B.
;
        PROC
;------------------------------------------------------------------
        XCALL FLAGS (0007000000,1)              ;Suppress STOP message

        CLOSE 1
        OPEN (1,O,'TT:')

        ;The file path can be written as:
        ;  "input.txt"                  (current directory)
        ;  "/directory/input.txt"       (complete path)
        ;  "DEV:input.txt"              (device DEV defined in shell)
        ;  "$DEV/input.txt"             (device DEV defined in shell)
        CLOSE 2
        OPEN (2,I,"input.txt")  [ERR=NOFIL]
        CLOSE 2

        ;Check directory (unix/linux systems)
        CLOSE 2
        OPEN (2,O,"/docs/.")    [ERR=NODIR]

        GOTO CLOS

;--------------------------------------------------------
NOFIL,  DISPLAY (1,"File input.txt not found!",10)
        GOTO CLOS

NODIR,  DISPLAY (1,"Directory /docs not found!",10)
        GOTO CLOS

CLOS,   CLOSE 1
        CLOSE 2
        STOP

DCL

$ if f$search( "input.txt" ) .eqs. ""
$ then
$  write sys$output "input.txt not found"
$ else
$  write sys$output "input.txt found"
$ endif
$ if f$search( "docs.dir" ) .eqs. ""
$ then
$  write sys$output "directory docs not found"
$ else
$  write sys$output "directory docs found"
$ endif
$ if f$search( "[000000]input.txt" ) .eqs. ""
$ then
$  write sys$output "[000000]input.txt not found"
$ else
$  write sys$output "[000000]input.txt found"
$ endif
$ if f$search( "[000000]docs.dir" ) .eqs. ""
$ then
$  write sys$output "directory [000000]docs not found"
$ else
$  write sys$output "directory [000000]docs found"
$ endif
Output:
$ @check_that_file_exists
input.txt found
directory docs not found
[000000]input.txt not found
directory [000000]docs not found

Delphi

program EnsureFileExists;

{$APPTYPE CONSOLE}

uses
  SysUtils;

begin
  if FileExists('input.txt') then
    Writeln('File "input.txt" exists.')
  else
    Writeln('File "input.txt" does not exist.');

  if FileExists('\input.txt') then
    Writeln('File "\input.txt" exists.')
  else
    Writeln('File "\input.txt" does not exist.');

  if DirectoryExists('docs') then
    Writeln('Directory "docs" exists.')
  else
    Writeln('Directory "docs" does not exists.');

  if DirectoryExists('\docs') then
    Writeln('Directory "\docs" exists.')
  else
    Writeln('Directory "\docs" does not exists.');
end.

DuckDB

Works with: DuckDB version V1.0

Files

DuckDB's table-valued glob() function can be used to check whether a particular file exists, at least if it can be read, but care must be used if the file's pathname has any glob characters. DuckDB's glob() is based on Python's glob.

For present purposes, it will be helpful to wrap glob() in a scalar function as follows:

create or replace function file_exists(fn) as (
   1 = (select count(file) from glob(fn)) );

Here's an illustrative transcript, where "D " denotes the DuckDB prompt:

D select file_exists('input.txt');
┌──────────────────────────┐
│ file_exists('input.txt') │
│         boolean          │
├──────────────────────────┤
│ true                     │
└──────────────────────────┘

# Notice the doubling of the singe-quote character in the filename:
D select file_exists('`Abdu''l-Bahá.txt'); 
┌──────────────────────────────────┐
│ file_exists('`Abdu''l-Bahá.txt') │
│             boolean              │
├──────────────────────────────────┤
│ false                            │
└──────────────────────────────────┘

D select file_exists('/tmp/docs/input.txt') as file;
┌─────────┐
│  file   │
│ boolean │
├─────────┤
│ false   │
└─────────┘

D select * from glob('/tmp/ExmanProcessMutex');
┌────────────────────────┐
│          file          │
│        varchar         │
├────────────────────────┤
│ /tmp/ExmanProcessMutex │
└────────────────────────┘

Directories

DuckDB does not have a function for determining whether a directory exists, though in an interactive session, one could use the .shell to "shell-out" to check, e.g.

.shell test -d docs

E

for file in [<file:input.txt>,
             <file:///input.txt>] {
  require(file.exists(),       fn { `$file is missing!` })
  require(!file.isDirectory(), fn { `$file is a directory!` })
}

for file in [<file:docs>,
             <file:///docs>] {
  require(file.exists(),      fn { `$file is missing!` })
  require(file.isDirectory(), fn { `$file is not a directory!` })
}

Elena

ELENA 4.x :

import system'io;
import extensions;

extension op
{
    validatePath()
        = self.Available.iif("exists","not found");
} 
   
public program()
{
    console.printLine("input.txt file ",File.assign("input.txt").validatePath());
 
    console.printLine("\input.txt file ",File.assign("\input.txt").validatePath());        

    console.printLine("docs directory ",Directory.assign("docs").validatePath());
 
    console.printLine("\docs directory ",Directory.assign("\docs").validatePath())
}

Elixir

File.regular?("input.txt")
File.dir?("docs")
File.regular?("/input.txt")
File.dir?("/docs")

Emacs Lisp

(file-exists-p "input.txt")
(file-directory-p "docs")
(file-exists-p "/input.txt")
(file-directory-p "/docs")

file-exists-p is true on both files and directories. file-directory-p is true only on directories. Both go through the file-name-handler-alist "magic filenames" mechanism so can act on remote files. On MS-DOS generally both / and \ work to specify the root directory.

Erlang

#!/usr/bin/escript
existence( true ) ->"exists";
existence( false ) ->"does not exist".

print_result(Type, Name, Flag) -> io:fwrite( "~s ~s ~s~n", [Type, Name, existence(Flag)] ).


main(_) ->
        print_result( "File", "input.txt", filelib:is_regular("input.txt") ),
        print_result( "Directory", "docs", filelib:is_dir("docs") ),
        print_result( "File", "/input.txt", filelib:is_regular("/input.txt") ),
        print_result( "Directory", "/docs", filelib:is_dir("/docs") ).

Euphoria

include file.e

procedure ensure_exists(sequence name)
    object x
    sequence s
    x = dir(name)
    if sequence(x) then
        if find('d',x[1][D_ATTRIBUTES]) then
            s = "directory"
        else
            s = "file"
        end if
        printf(1,"%s %s exists.\n",{name,s})
    else
        printf(1,"%s does not exist.\n",{name})
    end if
end procedure

ensure_exists("input.txt")
ensure_exists("docs")
ensure_exists("/input.txt")
ensure_exists("/docs")

F#

open System.IO
File.Exists("input.txt")
Directory.Exists("docs")
File.Exists("/input.txt")
Directory.Exists(@"\docs")

Factor

: print-exists? ( path -- )
    [ write ": " write ] [ exists? "exists." "doesn't exist." ? print ] bi ;

{ "input.txt" "/input.txt" "docs" "/docs" } [ print-exists? ] each

Forth

: .exists ( str len -- )
    2dup file-status nip 0= if
        ." exists: "
    else
        ." does not exist: "
    then
    type
;

s" input.txt" .exists cr
s" /input.txt" .exists cr
s" docs" .exists cr
s" /docs" .exists cr

Fortran

Works with: Fortran version 90 and later

Cannot check for directories in Fortran

LOGICAL :: file_exists
INQUIRE(FILE="input.txt", EXIST=file_exists)   ! file_exists will be TRUE if the file
                                               ! exists and FALSE otherwise
INQUIRE(FILE="/input.txt", EXIST=file_exists)

Actually, f90,f95 are able to deal with directory staff:

logical :: dir_e
! a trick to be sure docs is a dir
inquire( file="./docs/.", exist=dir_e )
if ( dir_e ) then
  write(*,*), "dir exists!"
else
  ! workaround: it calls an extern program...
  call system('mkdir docs')
end if

FreeBASIC

' FB 1.05.0 Win64

' Enable FileExists() function to be used
#include "file.bi"

' Use Win32 function to check if directory exists on Windows 10
Declare Function GetFileAttributes Lib "kernel32.dll" Alias "GetFileAttributesA" _
(ByVal lpFileName As ZString Ptr) As ULong

Const InvalidFileAttributes As ULong = -1UL
Const FileAttributeDirectory As ULong = &H10UL

Sub CheckFileExists(ByRef filePath As String)
  If FileExists(filePath) Then
    Print "'"; filePath; "' exists"
  Else
    Print "'"; filePath; "' does not exist"
  End If
End Sub

Sub CheckDirectoryExists(ByVal dirPath As ZString Ptr)
  Dim attrib As ULong = GetFileAttributes(dirPath) 
  Dim dirExists As ULong = attrib <> InvalidFileAttributes AndAlso (attrib And FileAttributeDirectory) <> 0 
  If dirExists Then
    Print "'"; *dirPath; "' exists"
  Else
    Print "'"; *dirPath; "' does not exist"
  End If 
End Sub

CheckFileExists(CurDir + "\input.txt")
Dim dirPath As String = CurDir + "\docs"
CheckDirectoryExists(StrPtr(dirPath))
CheckFileExists("c:\input.txt")
CheckDirectoryExists(StrPtr("c:\docs"))
Print
Print "Press any key to quit the program"
Sleep
Output:

All files and directories were created first. The files are empty:

'c:\FreeBasic\input.txt' exists
'c:\FreeBasic\docs' exists
'c:\input.txt' exists
'c:\docs' exists


Frink

This checks that the file exists and is a file, and that the directory exists, and is a directory. (Many of the samples on this page do not check that the files are actually a file or the directories are actually a directory.) It also tries to find various Unicode encodings of the "unusual" filename that may be encoded in different Unicode compositions (e.g. using "precomposed" or "decomposed" representations for some characters.

checkFile[filename] :=
{
   file = newJava["java.io.File", [filename]]
   if file.exists[] and file.isFile[]
      println["$filename is a file"]
   else
      println["$filename is not a file"]
}

checkDir[filename] :=
{
   file = newJava["java.io.File", [filename]]
   if file.exists[] and file.isDirectory[]
      println["$filename is a directory"]
   else
      println["$filename is not a directory"]
}

checkFile["input.txt"]
checkFile["/input.txt"]
checkDir["docs"]
checkDir["/docs"]

// This tests the "unusual" filename with various Unicode
// normalizations that would look identical to a human
// For example, the á character could be written as either
// the Unicode sequences
//    \u00e1   ('LATIN SMALL LETTER A WITH ACUTE')
// or
//    \u0061\u0301  ('LATIN SMALL LETTER A' 'COMBINING ACUTE ACCENT')
unusual = "`Abdu'l-Bahá.txt"    
checkFile[unusual]
checkFile[normalizeUnicode[unusual, "NFC"]]
checkFile[normalizeUnicode[unusual, "NFD"]]


FutureBasic

include "NSLog.incl"

CFURLRef url
url = fn URLFileURLWithPath( fn StringByExpandingTildeInPath(@"~/Desktop/input.txt") )
if (fn FileManagerFileExistsAtURL( url ) )
  NSLog( @"File \"input.txt\" exists." )
else
  NSLog( @"File \"input.txt\" does not exist at this location." )
end if

url = fn URLFileURLWithPath( fn StringByExpandingTildeInPath(@"~/Desktop/docs") )
if (fn FileManagerIsDirectoryAtURL( url ) )
  NSLog( @"Directory \"docs\" exists." )
else
  NSLog( @"Directory \"docs\" does not exist at this location." )
end if

HandleEvents

Gambas

Click this link to run this code

Public Sub Main()

If Exist(User.Home &/ "input.txt") Then Print "'input.txt' does exist in the Home folder"
If Not Exist("/input.txt") Then Print "'input.txt' does NOT exist in Root"                'Not messing With my Root files

If Exist(User.home &/ "docs/") Then Print "The folder '~/docs' does exist"
If Not Exist("/docs/") Then Print "The folder '/docs' does NOT exist"                     'Not messing With my Root files

File.Save(User.Home &/ "`Abdu'l-Bahá.txt", "")
If Exist(User.Home &/ "`Abdu'l-Bahá.txt") Then Print "'`Abdu'l-Bahá.txt' does exist (zero length and unusual name)"

End

Output:

'input.txt' does exist in the Home folder
'input.txt' does NOT exist in Root
The folder '~/docs' does exist
The folder '/docs' does NOT exist
'`Abdu'l-Bahá.txt' does exist (zero length and unusual name)


GAP

IsExistingFile("input.txt");     
IsDirectoryPath("docs");
IsExistingFile("/input.txt");
IsDirectoryPath("/docs");

Genie

[indent=4]
/*
   Check file exists, in Genie
   valac --pkg=gio-2.0 checkFile.gs
*/

init
    Intl.setlocale()

    files:array of string[] = {"input.txt", "docs",
    Path.DIR_SEPARATOR_S + "input.txt", Path.DIR_SEPARATOR_S + "docs", "`Abdu'l-Bahá.txt"}
    for f:string in files
        var file = File.new_for_path(f)
        var exists = file.query_exists()
        var dir = false
        if exists
            dir = file.query_file_type(0) == FileType.DIRECTORY
        print("%s %sexist%s%s", f, exists ? "" : "does not ", exists ? "s" : "", dir ? " and is a directory" : "")
Output:
prompt$ valac --pkg=gio-2.0 checkFile.gs
prompt$ ./checkFile
input.txt exists
docs exists and is a directory
/input.txt does not exist
/docs does not exist
`Abdu'l-Bahá.txt does not exist

For the run, input.txt was zero length.

Go

package main

import (
    "fmt"
    "os"
)

func printStat(p string) {
    switch i, err := os.Stat(p); {
    case err != nil:
        fmt.Println(err)
    case i.IsDir():
        fmt.Println(p, "is a directory")
    default:
        fmt.Println(p, "is a file")
    }
}

func main() {
    printStat("input.txt")
    printStat("/input.txt")
    printStat("docs")
    printStat("/docs")
}

Groovy

println new File('input.txt').exists()
println new File('/input.txt').exists()
println new File('docs').exists()
println new File('/docs').exists()

Haskell

import System.Directory (doesFileExist, doesDirectoryExist)

check :: (FilePath -> IO Bool) -> FilePath -> IO ()
check p s = do
  result <- p s
  putStrLn $
    s ++
    if result
      then " does exist"
      else " does not exist"

main :: IO ()
main = do
  check doesFileExist "input.txt"
  check doesDirectoryExist "docs"
  check doesFileExist "/input.txt"
  check doesDirectoryExist "/docs"

hexiscript

println "File \"input.txt\"? " + (exists "input.txt")
println "Dir \"docs\"?       " + (exists "docs/")
println "File \"/input.txt\"? " + (exists "/input.txt")
println "Dir \"/docs\"?       " + (exists "/docs/")

HicEst

   OPEN(FIle=   'input.txt', OLD, IOStat=ios, ERror=99)
   OPEN(FIle='C:\input.txt', OLD, IOStat=ios, ERror=99)
! ...
99 WRITE(Messagebox='!') 'File does not exist. Error message ', ios

HolyC

U0 FileExists(U8 *f) {
  if (FileFind(f) && !IsDir(f)) {
    Print("'%s' file exists.\n", f);
  } else {
    Print("'%s' file does not exist.\n", f);
  }
}

U0 DirExists(U8 *d) {
  if (IsDir(d)) {
    Print("'%s' directory exists.\n", d);
  } else {
    Print("'%s' directory does not exist.\n", d);
  }
}

FileExists("input.txt");
FileExists("::/input.txt");
DirExists("docs");
DirExists("::/docs");

i

concept exists(path) {
	open(path)
	errors {
		if error.DoesNotExist()
			print(path, " does not exist!")
		end
		return
	}
	print(path, " exists!")
}

software {
	exists("input.txt")
	exists("/input.txt")
	exists("docs")
	exists("/docs")
	exists("docs/Abdu'l-Bahá.txt")
}

Icon and Unicon

Icon doesn't support 'stat'; however, information can be obtained by use of the system function to access command line.

every dir := !["./","/"] do {
   write("file ", f := dir || "input.txt", if stat(f) then " exists." else " doesn't exist.") 
   write("directory ", f := dir || "docs", if stat(f) then " exists." else " doesn't exist.") 
   }

Note: Icon and Unicon accept both / and \ for directory separators.

IDL

print, FILE_TEST('input.txt')
print, FILE_TEST(PATH_SEP()+'input.txt')
print, FILE_TEST('docs', /DIRECTORY)
print, FILE_TEST(PATH_SEP()+'docs', /DIRECTORY)

J

require 'files'
fexist 'input.txt'
fexist '/input.txt'
direxist=: 2 = ftype
direxist 'docs'
direxist '/docs'

Java

This can be done with a File object.

new File("docs/input.txt").exists();
new File("/docs/input.txt").exists();

Zero-length files are not a problem, and return as existent.
Java supports UTF-16, so the unusual file name is not a problem.

new File("`Abdu'l-Bahá.txt").exists()
new File("`Abdu'l-Bah\u00E1.txt").exists();


Alternately

import java.io.File;
public class FileExistsTest {
   public static boolean isFileExists(String filename) {
       boolean exists = new File(filename).exists();
       return exists;
   }
   public static void test(String type, String filename) {
       System.out.println("The following " + type + " called " + filename + 
           (isFileExists(filename) ? " exists." : " not exists.")
       );
   }
   public static void main(String args[]) {
        test("file", "input.txt");
        test("file", File.separator + "input.txt");
        test("directory", "docs");
        test("directory", File.separator + "docs" + File.separator);
   }
}
Works with: Java version 7+
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
public class FileExistsTest{
   private static FileSystem defaultFS = FileSystems.getDefault();
   public static boolean isFileExists(String filename){
       return Files.exists(defaultFS.getPath(filename));
   }
   public static void test(String type, String filename){
       System.out.println("The following " + type + " called " + filename + 
           (isFileExists(filename) ? " exists." : " not exists.")
       );
   }
   public static void main(String args[]){
        test("file", "input.txt");
        test("file", defaultFS.getSeparator() + "input.txt");
        test("directory", "docs");
        test("directory", defaultFS.getSeparator() + "docs" + defaultFS.getSeparator());
   }
}

JavaScript

Javascript interpreters are now widely embedded in contexts which do have access to file systems, but the early context of browser scripting has precluded the inclusion of file system libraries in the definition of the language itself. Each non-browser JS context is likely to have its own home-grown and unstandardised file system library.

JScript

var fso = new ActiveXObject("Scripting.FileSystemObject");

fso.FileExists('input.txt');
fso.FileExists('c:/input.txt');
fso.FolderExists('docs');
fso.FolderExists('c:/docs');

macOS JavaScript for Automation

ES6: Sierra onwards

Translation of: Haskell

(Adopting function names used in the Haskell System.Directory library)

(() => {

    // SYSTEM DIRECTORY FUNCTIONS
    // FOR MAC OS 'JAVASCRIPT FOR AUTOMATION' SCRIPTING -----------------------

    // doesDirectoryExist :: String -> IO Bool
    const doesDirectoryExist = strPath => {
        const
            dm = $.NSFileManager.defaultManager,
            ref = Ref();
        return dm
            .fileExistsAtPathIsDirectory(
                $(strPath)
                .stringByStandardizingPath, ref
            ) && ref[0] === 1;
    };

    // doesFileExist :: String -> Bool
    const doesFileExist = strPath => {
        var error = $();
        return (
            $.NSFileManager.defaultManager
            .attributesOfItemAtPathError(
                $(strPath)
                .stringByStandardizingPath,
                error
            ),
            error.code === undefined
        );
    };

    // getCurrentDirectory :: String
    const getCurrentDirectory = () =>
        ObjC.unwrap($.NSFileManager.defaultManager.currentDirectoryPath);

    // getFinderDirectory :: String
    const getFinderDirectory = () =>
        Application('Finder')
        .insertionLocation()
        .url()
        .slice(7);

    // getHomeDirectory :: String
    const getHomeDirectory = () =>
        ObjC.unwrap($.NSHomeDirectory());

    // setCurrentDirectory :: String -> IO ()
    const setCurrentDirectory = strPath =>
        $.NSFileManager.defaultManager
        .changeCurrentDirectoryPath(
            $(strPath)
            .stringByStandardizingPath
        );

    // GENERIC FUNCTIONS FOR THE TEST -----------------------------------------

    // A list of functions applied to a list of arguments
    // <*> :: [(a -> b)] -> [a] -> [b]
    const ap = (fs, xs) => //
        [].concat.apply([], fs.map(f => //
            [].concat.apply([], xs.map(x => [f(x)]))));

    // show :: a -> String
    const show = x => JSON.stringify(x, null, 2);

    // TEST -------------------------------------------------------------------
    return (
        setCurrentDirectory('~/Desktop'),
        show(ap(
            [doesFileExist, doesDirectoryExist],
            ['input.txt', '/input.txt', 'docs', '/docs']
        ))
    );
})();
Output:

The first four booleans are returned by doesFileExist – the last four by doesDirectoryExist, which returns false in the case of files which do exist but are not directories.

[
  true,
  true,
  true,
  true,
  false,
  false,
  true,
  true
]

Julia

Works with: Julia version 0.6
@show isfile("input.txt")
@show isfile("/input.txt")
@show isdir("docs")
@show isdir("/docs")
@show isfile("")
@show isfile("`Abdu'l-Bahá.txt")

Klingphix

include ..\Utilitys.tlhy

"foo.bar" "w" fopen
"Hallo !" over fputs
fclose
 
"fou.bar" "r" fopen
dup 0 < ( ["Could not open 'fou.bar' for reading" print drop] [fclose] ) if

" " input
Output:
Could not open 'fou.bar' for reading

Kotlin

// version 1.0.6

import java.io.File

fun main(args: Array<String>) {
    val filePaths = arrayOf("input.txt", "c:\\input.txt", "zero_length.txt", "`Abdu'l-Bahá.txt")
    val dirPaths  = arrayOf("docs", "c:\\docs")
    for (filePath in filePaths) {
        val f = File(filePath)
        println("$filePath ${if (f.exists() && !f.isDirectory) "exists" else "does not exist"}")
    }
    for (dirPath in dirPaths) {
        val d = File(dirPath)
        println("$dirPath ${if (d.exists() && d.isDirectory) "exists" else "does not exist"}")
    }
}

LabVIEW

Library: LabVIEW CWD

This image is a VI Snippet, an executable image of LabVIEW code. The LabVIEW version is shown on the top-right hand corner. You can download it, then drag-and-drop it onto the LabVIEW block diagram from a file browser, and it will appear as runnable, editable code.


Lang

# Load the IO module
# Replace "<pathToIO.lm>" with the location where the io.lm Lang module was installed to without "<" and ">"
ln.loadModule(<pathToIO.lm>)

$file1 = [[io]]::fp.openFile(input.txt)
[[io]]::fp.existsFile($file1)
[[io]]::fp.closeFile($file1)

$file2 = [[io]]::fp.openFile(/input.txt)
[[io]]::fp.existsFile($file2)
[[io]]::fp.closeFile($file2)

$dir1 = [[io]]::fp.openFile(docs)
[[io]]::fp.existsFile($dir1)
[[io]]::fp.closeFile($dir1)

$dir2 = [[io]]::fp.openFile(/docs)
[[io]]::fp.existsFile($dir2)
[[io]]::fp.closeFile($dir2)

langur

The prop() function returns a hash of file/directory properties.

val printresult = fn*(file) {
    write file, ": "
    if val p = prop(file) {
        if p'isdir {
            writeln "is directory"
        } else {
            writeln "is file"
        }
    } else {
        writeln "nothing"
    }
}

printresult "input.txt"
printresult "/input.txt"
printresult "docs"
printresult "/docs"

Lasso

// local file
file_exists('input.txt')

// local directory
file_exists('docs')

// file in root file system (requires permissions at user OS level)
file_exists('//input.txt')

// directory in root file system (requires permissions at user OS level)
file_exists('//docs')

LFE

From the LFE REPL:

> (: filelib is_regular '"input.txt")
false
> (: filelib is_dir '"docs")
false
> (: filelib is_regular '"/input.txt")
false
> (: filelib is_dir '"/docs"))
false

Liberty BASIC

'fileExists.bas - Show how to determine if a file exists
dim info$(10,10)
input "Type a file path (ie. c:\windows\somefile.txt)?"; fpath$
if fileExists(fpath$) then
    print fpath$; " exists!"
else
    print fpath$; " doesn't exist!"
end if
end

'return a true if the file in fullPath$ exists, else return false
function fileExists(fullPath$)
    files pathOnly$(fullPath$), filenameOnly$(fullPath$), info$()
    fileExists = val(info$(0, 0)) > 0
end function

'return just the directory path from a full file path
function pathOnly$(fullPath$)
    pathOnly$ = fullPath$
    while right$(pathOnly$, 1) <> "\" and pathOnly$ <> ""
        pathOnly$ = left$(pathOnly$, len(pathOnly$)-1)
    wend
end function

'return just the filename from a full file path
function filenameOnly$(fullPath$)
    pathLength = len(pathOnly$(fullPath$))
    filenameOnly$ = right$(fullPath$, len(fullPath$)-pathLength)
end function

Little

if (exists("input.txt")) {
    puts("The file \"input.txt\" exist");   
}
if (exists("/input.txt")) {
    puts("The file \"/input.txt\" exist");  
}
if (exists("docs")) {
    puts("The file \"docs\" exist");    
}
if (exists("/docs")) {
    puts("The file \"/docs\" exist");   
}

LiveCode

there is a file "/input.txt"
there is a file "input.txt"
there is a folder "docs"
there is a file "/docs/input.txt"

LiveCode also allows setting a default folder for subsequent file commands. To check if a file exists in the doc folder

set the defaultFolder to "docs"
there is a file "input.txt"

Works with: UCB Logo
show file? "input.txt
show file? "/input.txt
show file? "docs
show file? "/docs

Alternatively, one can set a file prefix used for subsequent file commands.

setprefix "/
show file? "input.txt

Lua

For directories, the following only works on platforms on which directories can be opened for reading like files.

function output( s, b )
    if b then
        print ( s, " does not exist." )
    else
        print ( s, " does exist." )
    end    
end

output( "input.txt",  io.open( "input.txt", "r" ) == nil )
output( "/input.txt", io.open( "/input.txt", "r" ) == nil )
output( "docs",  io.open( "docs", "r" ) == nil )
output( "/docs", io.open( "/docs", "r" ) == nil )

The following more portable solution uses LuaFileSystem.

require "lfs"
for i, path in ipairs({"input.txt", "/input.txt", "docs", "/docs"}) do
    local mode = lfs.attributes(path, "mode")
    if mode then
        print(path .. " exists and is a " .. mode .. ".")
    else
        print(path .. " does not exist.")
    end
end

M2000 Interpreter

Report print proportional text using word wrap, and justification. Can be used to calculate lines, and to render form a line, a number of lines. We can specify the width of the text, and by moving the cursor horizontal we can specify the left margin. This statement can be used to any layer, including user forms and printer page.

Module ExistDirAndFile {
      Let WorkingDir$=Dir$, RootDir$="C:\"
 
      task(WorkingDir$)
      task(RootDir$)
      Dir User ' return to user directroy
 
      Sub task(WorkingDir$)
            Local counter
            Dir WorkingDir$
            If Not Exist.Dir("docs") then Report  "docs not exist in "+WorkingDir$ : counter++
            If Not Exist("output.txt") Then {
                  Report "output.txt not exist in "+ WorkingDir$ : counter++
            } Else.if Filelen("output.txt")=0 Then Report "output.txt has zero length"
            If counter =0 then Report  WorkingDir$+ " has docs directory and file output.txt"
      End Sub
}
ExistDirAndFile

Maple

with(FileTools):
Exists("input.txt");
Exists("docs") and IsDirectory("docs");
Exists("/input.txt");
Exists("/docs") and IsDirectory("/docs");

Mathematica / Wolfram Language

wd = NotebookDirectory[];
FileExistsQ[wd <> "input.txt"]
DirectoryQ[wd <> "docs"]

FileExistsQ["/" <> "input.txt"]
DirectoryQ["/" <> "docs"]

MATLAB / Octave

 exist('input.txt','file') 
 exist('/input.txt','file') 
 exist('docs','dir') 
 exist('/docs','dir')

MAXScript

-- Here
doesFileExist "input.txt"
(getDirectories "docs").count == 1
-- Root
doesFileExist "\input.txt"
(getDirectories "C:\docs").count == 1

Modula-3

MODULE FileTest EXPORTS Main;

IMPORT IO, Fmt, FS, File, OSError, Pathname;

PROCEDURE FileExists(file: Pathname.T): BOOLEAN =
  VAR status: File.Status;
  BEGIN
    TRY
      status := FS.Status(file);
      RETURN TRUE;
    EXCEPT
    | OSError.E => RETURN FALSE;
    END;
  END FileExists;

BEGIN
  IO.Put(Fmt.Bool(FileExists("input.txt")) & "\n");
  IO.Put(Fmt.Bool(FileExists("/input.txt")) & "\n");
  IO.Put(Fmt.Bool(FileExists("docs/")) & "\n");
  IO.Put(Fmt.Bool(FileExists("/docs")) & "\n");
END FileTest.

Nanoquery

import Nanoquery.IO

def exists(fname)
	f = new(File, fname)

	return f.exists()
end

Neko

/**
 Check that file/dir exists, in Neko
*/

var sys_exists = $loader.loadprim("std@sys_exists", 1)
var sys_file_type = $loader.loadprim("std@sys_file_type", 1)
var sys_command = $loader.loadprim("std@sys_command", 1)

var name = "input.txt"
$print(name, " exists as file: ", sys_exists(name), "\n")

$print(name = "docs", " exists as dir: ", sys_exists(name) && sys_file_type(name) == "dir", "\n")
$print(name = "neko", " exists as dir: ", sys_exists(name) && sys_file_type(name) == "dir", "\n")

$print(name = "/input.txt", " exists as file: ", sys_exists(name) && sys_file_type(name) == "file", "\n")
$print(name = "/docs", " exists as dir: ", sys_exists(name) && sys_file_type(name) == "dir", "\n")
$print(name = "/tmp", " exists as dir: ", sys_exists(name) && sys_file_type(name) == "dir", "\n")

/* bonus round */
name = "empty.txt"
var stat_size = $loader.loadprim("std@sys_stat", 1)(name).size
$print(name, " exists as empty file: ", sys_exists(name) && stat_size == 0, "\n")

name = "`Abdu'l-Bahá.txt"
$print(name, " exists as file: ", sys_exists(name) && sys_file_type(name) == "file", "\n")
Output:
prompt$ nekoc exists.neko
prompt$ neko exists.n
input.txt exists as file: true
docs exists as dir: false
neko exists as dir: true
/input.txt exists as file: false
/docs exists as dir: false
/tmp exists as dir: true
empty.txt exists as empty file: true
`Abdu'l-Bahá.txt exists as file: true

Nemerle

Translation of: C#
using System.Console;
using System.IO;
 
WriteLine(File.Exists("input.txt"));
WriteLine(File.Exists("/input.txt"));
WriteLine(Directory.Exists("docs"));
WriteLine(Directory.Exists("/docs"));

NetRexx

/* NetRexx */
options replace format comments java crossref symbols binary

runSample(arg)
return

-- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
method isExistingFile(fn) public static returns boolean
  ff = File(fn)
  fExists = ff.exists() & ff.isFile()
  return fExists

-- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
method isExistingDirectory(fn) public static returns boolean
  ff = File(fn)
  fExists = ff.exists() & ff.isDirectory()
  return fExists

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method runSample(arg) private static
  parse arg files
  if files = '' then files = 'input.txt F docs D /input.txt F /docs D'
  loop while files.length > 0
    parse files fn ft files
    select case(ft.upper())
      when 'F' then do
        if isExistingFile(fn) then ex = 'exists'
        else                       ex = 'does not exist'
        say 'File '''fn'''' ex
        end
      when 'D' then do
        if isExistingDirectory(fn) then ex = 'exists'
        else                            ex = 'does not exist'
        say 'Directory '''fn'''' ex
        end
      otherwise do
        if isExistingFile(fn) then ex = 'exists'
        else                       ex = 'does not exist'
        say 'File '''fn'''' ex
        end
      end
    end

  return

NewLISP

(dolist (file '("input.txt" "/input.txt"))
  (if (file? file true)
      (println "file " file " exists")))

(dolist (dir '("docs" "/docs"))
  (if (directory? dir)
      (println "directory " dir " exists")))

Nim

import os

echo fileExists "input.txt"
echo fileExists "/input.txt"
echo dirExists "docs"
echo dirExists "/docs"

Nu

Works with: Nushell version 0.97.1
['input.txt' 'doc' '/input.txt' '/doc'] | each { {file: $in exists: ($in | path exists)} }
Output (example):
╭───┬────────────┬────────╮
│ # │    file    │ exists │
├───┼────────────┼────────┤
│ 0 │ input.txt  │ true   │
│ 1 │ doc        │ false  │
│ 2 │ /input.txt │ false  │
│ 3 │ /doc       │ true   │
╰───┴────────────┴────────╯

Objeck

use IO;

bundle Default {
  class Test {
    function : Main(args : String[]) ~ Nil {
      File->Exists("input.txt")->PrintLine();
      File->Exists("/input.txt")->PrintLine();
      Directory->Exists("docs")->PrintLine();
      Directory->Exists("/docs")->PrintLine();
    }
}

Objective-C

NSFileManager *fm = [NSFileManager defaultManager];
NSLog(@"input.txt %s", [fm fileExistsAtPath:@"input.txt"] ? @"exists" : @"doesn't exist");
NSLog(@"docs %s", [fm fileExistsAtPath:@"docs"] ? @"exists" : @"doesn't exist");

Odin

package main

import "core:os"

main :: proc() {
  os.exists("input.txt")
  os.exists("/input.txt")
  os.exists("docs")
  os.exists("/docs")
}

OCaml

Sys.file_exists "input.txt";;
Sys.file_exists "docs";;
Sys.file_exists "/input.txt";;
Sys.file_exists "/docs";;

ooRexx

/**********************************************************************
* exists(filespec)
* returns 1   if filespec identifies a file with size>0
*                (a file of size 0 is deemed not to exist.)
*             or a directory
*         0   otherwise
* 09.06.2013 Walter Pachl (retrieved from my toolset)
**********************************************************************/
exists:
  parse arg spec
  call sysfiletree spec, 'LIST', 'BL'
  if list.0\=1 then return 0        -- does not exist
  parse var list.1 . . size flags .
  if size>0 then return 1           -- real file
  If substr(flags,2,1)='D' Then Do
    Say spec 'is a directory'
    Return 1
    End
  If size=0 Then Say spec 'is a zero-size file'
  Return 0

Oz

declare
  [Path] = {Module.link ['x-oz://system/os/Path.ozf']}
in
  {Show {Path.exists "docs"}}
  {Show {Path.exists "input.txt"}}
  {Show {Path.exists "/docs"}}
  {Show {Path.exists "/input.txt"}}

PARI/GP

trap(,"does not exist",read("input.txt");"exists")
trap(,"does not exist",read("c:\\input.txt");"exists")
trap(,"does not exist",read("c:\\dirname\\nul");"exists")

A better version would use externstr.

Under PARI it would typically be more convenient to use C methods.

Pascal

See Delphi

PascalABC.NET

##
uses System.IO;

FileExists('input.txt').Println;
FileExists('\input.txt').Println;
system.IO.Directory.Exists('docs').Println;
system.IO.Directory.Exists('\docs').Println;

Perl

use File::Spec::Functions qw(catfile rootdir);
# here
print -e 'input.txt';
print -d 'docs';
# root dir
print -e catfile rootdir, 'input.txt';
print -d catfile rootdir, 'docs';

Without a Perl Module

A 1 is printed if the file or dir exists.

perl -e 'print -e "./input.txt", "\n";'
perl -e 'print -d "./docs", "\n";'
perl -e 'print -e "/input.txt", "\n";'
perl -e 'print -d "/docs", "\n";'

Phix

Library: Phix/basics
without js -- (file i/o)
procedure check(string name)
    bool bExists = file_exists(name),
         bDir = get_file_type(name)=FILETYPE_DIRECTORY
    string exists = iff(bExists?"exists":"does not exist"),
           dfs = iff(bExists?iff(bDir?"directory ":"file "):"")
    printf(1,"%s%s %s.\n",{dfs,name,exists})
end procedure
 
check("input.txt")
check("docs")
check("/input.txt")
check("/docs")
check("/pagefile.sys")
check("/Program Files (x86)")
Output:
file input.txt exists.
directory docs exists.
/input.txt does not exist.
/docs does not exist.
file /pagefile.sys exists.
directory /Program Files (x86) exists.

Phixmonti

"foo.bar" "w" fopen
"Hallo !" over fputs
fclose

"fou.bar" "r" fopen
dup 0 < if "Could not open 'foo.bar' for reading" print drop else fclose endif

PHP

if (file_exists('input.txt')) echo 'input.txt is here right by my side';
if (file_exists('docs'     )) echo 'docs is here with me';
if (file_exists('/input.txt')) echo 'input.txt is over there in the root dir';
if (file_exists('/docs'    )) echo 'docs is over there in the root dir';

PicoLisp

(if (info "file.txt")
   (prinl "Size: " (car @) " bytes, last modified " (stamp (cadr @) (cddr @)))
   (prinl "File doesn't exist") )

# for directory existing 
# Nehal-Singhal 2018-05-25

(if (info "./docs") 
  (print 'exists) 
  (print 'doesNotExist)))

# To verify if it's really a directory, (CAR of return value will be 'T').
# abu 2018-05-25

  (let I (info "./docs")
      (prinl
         (nond
            (I "Does not exist")
            ((=T (car I)) "Is not a directory")
            (NIL "Directory exists") ) ) )

Pike

import Stdio;

int main(){
   if(exist("/var")){
      write("/var exists!\n");
   }

   if(exist("file-exists.pike")){
      write("I exist!\n");
   }
}

PL/I

*Process source or(!);
 /*********************************************************************
 * 20.10.2013 Walter Pachl
 * 'set dd:f=d:\_l\xxx.txt,recsize(300)'
 * 'tex'
 *********************************************************************/
 tex: Proc Options(main);
 Dcl fid Char(30) Var Init('D:\_l\tst.txt');
 Dcl xxx Char(30) Var Init('D:\_l\nix.txt');
 Dcl r   Char(1000) Var;
 Dcl f Record input;
 On Undefinedfile(f) Goto label;
 Open File(f) Title('/'!!fid);
 Read file(f) Into(r);
 Put Skip List('First line of file '!!fid!!': '!!r);
 Close File(f);
 Open File(f) Title('/'!!xxx);
 Read file(f) Into(r);
 Put Skip List(r);
 Close File(f);
 Label: Put Skip List('File '!!xxx!!' not found');
 End;
Output:
  
First line of file D:\_l\tst.txt: Test line 1
File D:\_l\nix.txt not found    

PL/M

This sample assumes that the original 8080 PL/M compiler is used and that the program will be running under CP/M. CP/M doesn't have a hierarchical file-system, so there are no folders or directories. This sample looks for INPUT.TXT on the current drive and also on the D: drive. An error will occur if there is no D: drive, so it is best not to run this if you haven't got one... :)
Note that CP/M restricts file names to 7-bit ascii upper-case and not all non-letter, non-digit characters can be used.
CP/M filenames are up to 8 characters long with an optional, up to three character extension.

100H:

   DECLARE FCB$SIZE      LITERALLY '36';

   BDOS: PROCEDURE( FN, ARG )BYTE; /* CP/M BDOS SYSTEM CALL, RETURNS A VALUE */
      DECLARE FN BYTE, ARG ADDRESS;
      GOTO 5;
   END BDOS;
   BDOS$P: PROCEDURE( FN, ARG );   /* CP/M BDOS SYSTEM CALL, NO RETURN VALUE */
      DECLARE FN BYTE, ARG ADDRESS;
      GOTO 5;
   END BDOS$P;
   PRINT$CHAR:   PROCEDURE( C ); DECLARE C BYTE;    CALL BDOS$P( 2, C );   END;
   PRINT$STRING: PROCEDURE( S ); DECLARE S ADDRESS; CALL BDOS$P( 9, S );   END;
   PRINT$NL:     PROCEDURE; CALL PRINT$STRING( .( 0DH, 0AH, '$' ) );       END;
   SEARCH$FIRST: PROCEDURE( FCB )BYTE;   /* RETURN 0, 1, 2, 3 IF FILE IN FCB */
      DECLARE FCB ADDRESS;               /*        EXISTS, 255 OTHERWISE     */
      RETURN BDOS( 17, FCB );
   END SEARCH$FIRST ;

   INIT$FCB: PROCEDURE( FCB, NAME );  /* INITIALISE A FILE-CONTROL-BLOCK     */
      DECLARE ( FCB, NAME ) ADDRESS;  /*     SETTING THE FILE NAME           */
      DECLARE ( F$PTR, N$PTR, X$PTR ) ADDRESS;
      DECLARE F BASED F$PTR BYTE, N BASED N$PTR BYTE;
      DECLARE BLANKS ( 5 )BYTE INITIAL( ' ', ' ', ' ', ' ', '$' );
      X$PTR = .BLANKS;
      N$PTR = NAME + 1;
      F$PTR = FCB;
      IF N <> ':' THEN DO;            /* NO DRIVE LETTER                     */
         F     = 0;
         N$PTR = NAME;
         END;
      ELSE DO;                        /* FIRST CHAR IS THE DRIVE LETTER      */
         N$PTR = NAME;
         F     = ( N + 1 ) - 'A';
         N$PTR = N$PTR + 2;
      END;
      DO F$PTR = FCB + 1 TO FCB + 8;  /* NAME                                */
         IF      N = '$' THEN N$PTR = .BLANKS;
         ELSE IF N = '.' THEN DO;     /* START OF THE EXTENSION              */
            X$PTR =  N$PTR + 1;
            N$PTR = .BLANKS;
         END;
         F     = N;
         N$PTR = N$PTR + 1;
      END;
      N$PTR = X$PTR;                  /* EXTENSION                           */
      DO F$PTR = FCB + 9 TO FCB + 11;
         IF N = '$' THEN N$PTR =.BLANKS;
         F     = N;
         N$PTR = N$PTR + 1;
      END;
      DO F$PTR = FCB + 12 TO FCB + ( FCB$SIZE - 1 ); /* OTHER FIELDS         */
         F = 0;
      END;
   END INIT$FCB ;

   EXISTS: PROCEDURE( FCB )BYTE; /* RETURNS TRUE IF THE FILE NAMED IN THE    */
      DECLARE FCB ADDRESS;       /*                 FCB EXISTS               */
      RETURN ( SEARCH$FIRST( FCB ) < 4 );
   END EXISTS ;

   DECLARE FCB$1$DATA ( FCB$SIZE )BYTE;  /* DECLARE A FILE-CONTROL-BLOCK     */
   DECLARE FCB$1 ADDRESS;
   FCB$1 = .FCB$1$DATA;

   /* CP/M DOES NOT HAVE DIRECTORIES/FOLDERS - THIS TESTS FOR INPUT.TXT IN   */
   /* THE CURRENT DEFAULT DRIVE                                              */
   CALL INIT$FCB( FCB$1, .'INPUT.TXT$' );
   CALL PRINT$STRING( .'INPUT.TXT: $' );
   IF EXISTS( FCB$1 ) THEN CALL PRINT$STRING( .'EXISTS$' );
                      ELSE CALL PRINT$STRING( .'DOES NOT EXIST$' );
   CALL PRINT$NL;

   /* CHECK FOR INPUT.TXT IN THE D: DRIVE                                    */
   /* !!! THIS WILL CAUSE AN ERROR IF THERE IS NO DRIVE D:               !!! */
   /* !!! OR THERE IS NO DISC IN DRIVE D:                                !!! */
   CALL INIT$FCB( FCB$1, .'D:INPUT.TXT$' );
   CALL PRINT$STRING( .'D:INPUT.TXT: $' );
   IF EXISTS( FCB$1 ) THEN CALL PRINT$STRING( .'EXISTS$' );
                      ELSE CALL PRINT$STRING( .'DOES NOT EXIST$' );
   CALL PRINT$NL;

EOF
Output:

Assuming there is no INPUT.TXT on the current drive, but there is one on D:.

INPUT.TXT: DOES NOT EXIST
D:INPUT.TXT: EXISTS

Assuming there is no INPUT.TXT on the current drive and there os no D: drive.

INPUT.TXT: DOES NOT EXIST
D:INPUT.TXT:
Bdos Err on A: Select

Plain English

To run:
Start up.
\ In the current working directory
Check that ".\input.txt" is in the file system.
Check that ".\docs\" is in the file system.
\ In the filesystem root
Check that "C:\input.txt" is in the file system.
Check that "C:\docs\" is in the file system.
Wait for the escape key.
Shut down.

To check that a path is in the file system:
If the path is in the file system, write the path then " exists" to the output; exit.
If the path is not in the file system, write the path then " does not exist" to the output; exit.

Pop11

sys_file_exists('input.txt') =>
sys_file_exists('/input.txt') =>
sys_file_exists('docs') =>
sys_file_exists('/docs') =>

Note that the above literally checks for existence. Namely sys_file_exists returns true if file exists but can not be read.

The only sure method to check if file can be read is to try to open it. If one just wants to check if file is readable the following may be useful:

;;; Define an auxilary function, returns boolean
define file_readable(fname);
   lvars f = sysopen(fname, 0, true, `A`);
   if f then
       sysclose(f);
       return (true);
   else
       return (false);
   endif;
enddefine;

The above works but is not the only way or the best way to check status of a file in Pop11. There is a very general procedure sys_file_stat that allows interrogation of a file or directory. The full documentation can be seen in the online documentation (search for sys_file_stat):

http://wwwcgi.rdg.ac.uk:8081/cgi-bin/cgiwrap/wsi14/poplog/pop11/ref/sysio

http://www.poplog.org/docs/popdocs/pop11/ref/sysio

http://www.cs.bham.ac.uk/research/projects/poplog/doc/popref/sysio (Not so well formatted).

Users can easily define special cases of the general procedure.

PowerShell

 if (Test-Path -Path .\input.txt) {
   write-host "File input exist"
}
else {
   write-host "File input doesn't exist"
}

Prolog

Works with: SWI-Prolog version 6.6
exists_file('input.txt'),
exists_directory('docs').

exits_file('/input.txt'),
exists_directory('/docs').

PureBasic

result = ReadFile(#PB_Any, "input.txt")
If result>0 : Debug "this local file exists"
  Else : Debug "result=" +Str(result) +" so this local file is missing"
EndIf 

result = ReadFile(#PB_Any, "/input.txt")
If result>0 : Debug "this root file exists"
  Else : Debug "result=" +Str(result) +" so this root file is missing"
EndIf 

result = ExamineDirectory(#PB_Any,"docs","")
If result>0 : Debug "this local directory exists"
  Else : Debug "result=" +Str(result) +" so this local directory is missing"
EndIf 

result = ExamineDirectory(#PB_Any,"/docs","")
If result>0 : Debug "this root directory exists"
  Else : Debug "result=" +Str(result) +" so this root directory is missing"
EndIf

Python

import os

os.path.isfile("input.txt")
os.path.isfile("/input.txt")
os.path.isdir("docs")
os.path.isdir("/docs")

The more generic os.path.exists(path) function will return True if the path exists, being it either a regular file or a directory.

QB64

$NOPREFIX
PRINT DIREXISTS("docs")
PRINT DIREXISTS("\docs")
PRINT FILEEXISTS("input.txt")
PRINT FILEEXISTS("\input.txt")

R

file.exists("input.txt")
file.exists("/input.txt")
file.exists("docs")
file.exists("/docs")

# or
file.exists("input.txt", "/input.txt", "docs", "/docs")

The function file.exists returns a logical value (or a vector of logical values if more than one argument is passed)

This works with special names:

file.exists("`Abdu'l-Bahá.txt")

Racket

#lang racket

;; here
(file-exists? "input.txt")
(file-exists? "docs")

;; in the root
(file-exists? "/input.txt")
(file-exists? "/docs")

;; or in the root with relative paths
(parameterize ([current-directory "/"])
  (and (file-exists? "input.txt")
       (file-exists? "docs")))

Raku

(formerly Perl 6)

my $path = "/etc/passwd";
say $path.IO.e ?? "Exists" !! "Does not exist";

given $path.IO {
    when :d { say "$path is a directory"; }
    when :f { say "$path is a regular file"; }
    when :e { say "$path is neither a directory nor a file, but it does exist"; }
    default { say "$path does not exist" }
}

when internally uses the smart match operator ~~, so when :e really does $given ~~ :e instead of the method call $given.e; both test whether the file exists.

run ('touch', "♥ Unicode.txt");

say "♥ Unicode.txt".IO.e;      # "True"
say "♥ Unicode.txt".IO ~~ :e;  # same

Raven

'input.txt'  exists if 'input.txt exists'  print
'/input.txt' exists if '/input.txt exists' print
'docs'  isdir if 'docs exists and is a directory'  print
'/docs' isdir if '/docs exists and is a directory' print

REBOL

exists? %input.txt
exists? %docs/

exists? %/input.txt
exists? %/docs/

Red

exists? %input.txt
exists? %docs/
exists? %/c/input.txt
exists? %/c/docs/
exists? %//input.txt
exists? %//docs/

>> exists? %`Abdu'l-Bahá.txt
== true

REXX

version 1

Works with: PC/REXX
Works with: Personal REXX
Works with: Regina
/*REXX program creates a new empty file and directory in current directory and root dir.*/
fn= 'input.txt'                                  /*default name of a file.              */
dn= 'docs'                                       /*default name of a directory (folder).*/
@.1= 'current directory';  @.2= 'root directory' /*messages used to indicate which pass.*/
parse upper version v                            /*obtain name of the REXX being used.  */
regina= pos('REGINA'  , v)\==0                   /*is this the Regina REXX being used?  */
r4    = pos('REXX-R4' , v)\==0                   /*is this the R4     REXX being used?  */
@doesnt= "doesn't exist in the"
@does  = "does exist in the"

 do j=1  for 2;    say                           /* [↑]  perform these statements twice.*/
 if stream(fn, 'C', "QUERY EXISTS")==''  then say 'file '       fn   @doesnt   @.j
                                         else say 'file '       fn   @does     @.j

 if j==2  then iterate
 if stream(dn, 'C', "QUERY EXISTS")==''  then say 'directory'   dn   @doesnt   @.j
                                         else say 'directory'   dn   @does     @.j
 if j==1  then select
               when regina  then call chdir    '\'    /*use Regina's version of  CHDIR. */
               when r4      then call stream   '\', "C", 'CHDIR'        /*R4's version. */
               otherwise         call doschdir '\'    /*PC/REXX & Personal REXX version.*/
               end   /*select*/
 end   /*j*/                                     /*stick a fork in it,  we're all done. */

version 2

Works with: ARexx
/* Check if a file already exists */
filename='file.txt'
IF ~Openfile(filename) THEN CALL Openfile(':'filename)
EXIT 0
Openfile:
IF ~Exists(filename) THEN RETURN 0
CALL Open(filehandle,filename,'APPEND')
RETURN 1

Ring

aFile = "C:\Ring\ReadMe.txt"
see aFile
if Fexists(aFile) see " exists" + nl
else see " doesn't exist" + nl ok

RLaB

RLaB provides two user functions for the task, isfile and isdir.

>> isdir("docs")
  0
>> isfile("input.txt")
  0

RPL

The 2 functions below take a word as an argument and return a boolean stating the presence or not of a 'file' (a 'variable' in RPL jargon) or a directory corresponding to the word.

« VARS SWAP POS 
» 'ISHERE?' STO

« PATH HOME
  VARS ROT POS 
  SWAP EVAL              @ Back to initial directory
» 'ISHOME?' STO

Ruby

File.exist? only checks if a file exists; it can be a regular file, a directory, or something else. File.file? or File.directory? checks for a regular file or a directory. Ruby also allows FileTest.file? or FileTest.directory?.

File.file?("input.txt")
File.file?("/input.txt")
File.directory?("docs")
File.directory?("/docs")

The next program runs all four checks and prints the results.

["input.txt", "/input.txt"].each { |f|
  printf "%s is a regular file? %s\n", f, File.file?(f) }
["docs", "/docs"].each { |d|
  printf "%s is a directory? %s\n", d, File.directory?(d) }

Run BASIC

files #f,"input.txt"
if #f hasanswer() = 1 then print "File does not exist"
files #f,"docs"
if #f hasanswer() = 1 then print "File does not exist"
if #f isDir()     = 0 then print "This is a directory"

Rust

use std::fs;

fn main() {
    for file in ["input.txt", "docs", "/input.txt", "/docs"].iter() {
        match fs::metadata(file) {
            Ok(attr) => {
                if attr.is_dir() {
                    println!("{} is a directory", file);
                }else {
                    println!("{} is a file", file);
                }
            },
            Err(_) => {
                println!("{} does not exist", file);
            }
        };
    }
}

Scala

Library: Scala
import java.nio.file.{ Files, FileSystems }

object FileExistsTest extends App {

  val defaultFS = FileSystems.getDefault()
  val separator = defaultFS.getSeparator()

  def test(filename: String) {
    val path = defaultFS.getPath(filename)

    println(s"The following ${if (Files.isDirectory(path)) "directory" else "file"} called $filename" +
      (if (Files.exists(path)) " exists." else " not exists."))
  }

  // main
  List("output.txt", separator + "output.txt", "docs", separator + "docs" + separator).foreach(test)
}

Scheme

Works with: Scheme version R6RS

[1]

(file-exists? filename)

Seed7

$ include "seed7_05.s7i";

const proc: main is func
  begin
    writeln(fileType("input.txt") = FILE_REGULAR);
    writeln(fileType("/input.txt") = FILE_REGULAR);
    writeln(fileType("docs") = FILE_DIR);
    writeln(fileType("/docs") = FILE_DIR);
  end func;

SenseTalk

	
put file "input.txt" exists	
put folder "docs" exists
 		 		
put file "/input.txt" exists	
put there is a folder "/docs"

Sidef

# Here
say (Dir.cwd  + %f'input.txt' -> is_file);
say (Dir.cwd  + %d'docs'      -> is_dir);

# Root
say (Dir.root + %f'input.txt' -> is_file);
say (Dir.root + %d'docs'      -> is_dir);

NOTE: To check only for existence, use the method exists

Slate

(File newNamed: 'input.txt') exists
(File newNamed: '/input.txt') exists
(Directory root / 'input.txt') exists
(Directory newNamed: 'docs') exists
(Directory newNamed: '/docs') exists

Smalltalk

Squeak has no notion of 'current directory' because it isn't tied to the shell that created it.

FileDirectory new fileExists: 'c:\serial'.
(FileDirectory on: 'c:\') directoryExists: 'docs'.

In GNU Smalltalk instead you can do:

(Directory name: 'docs') exists ifTrue: [ ... ]
(Directory name: 'c:\docs') exists ifTrue: [ ... ]
(File name: 'serial') isFile ifTrue: [ ... ]
(File name: 'c:\serial') isFile ifTrue: [ ... ]

Using exists in the third and fourth case will return true for directories too.

Standard ML

OS.FileSys.access ("input.txt", []);
OS.FileSys.access ("docs", []);
OS.FileSys.access ("/input.txt", []);
OS.FileSys.access ("/docs", []);

Stata

Mata has functions to check the existence of files and directories:

mata
fileexists("input.txt")
direxists("docs")
end

It's not as straightforward in Stata's macro language. For files, use confirm. Since it throws an error when the file does not exist, use capture and check _rc afterwards.

capture confirm file input.txt
if !_rc {
	* do something if the file exists
}

It's not possible to check the existence of a directory with confirm. One may use the confirmdir package from SSC. The confirmdir command saves the current directory, then tries to chdir to the directory to test (with capture to prevent an error). Then the value of _rc is put in a stored result. Example of use:

confirmdir docs
if !`r(confirmdir)' {
	* do something if the directory exists
}

The command works with special names, but one has to be careful: the name "`Abdu'l-Bahá.txt" contains a backquote, which is used to denote macros in Stata. So this character must be escaped with a backslash:

confirm file "\`Abdu'l-Bahá.txt"

Tcl

Taking the meaning of the task from the DOS example:

if { [file exists "input.txt"] } {
    puts "input.txt exists"
} 

if { [file exists [file nativename "/input.txt"]] } {
    puts "/input.txt exists"
} 

if { [file isdirectory "docs"] } {
    puts "docs exists and is a directory"
}

if { [file isdirectory [file nativename "/docs"]] } {
    puts "/docs exists and is a directory"
}

Note that these operations do not require the use of file nativename on either Windows or any version of Unix.

Toka

[ "R" file.open dup 0 <> [ dup file.close ] ifTrue 0 <> ] is exists?
" input.txt" exists? .
" /input.txt" exists? .
" docs" exists? .
" /docs" exists? .

True BASIC

SUB opener (a$)
    WHEN EXCEPTION IN
         OPEN #1: NAME f$
         PRINT f$; " exists"
    USE
         PRINT f$; " not exists"
    END WHEN
    CLOSE #1
END SUB

LET f$ = "input.txt"
CALL opener (f$)
LET f$ = "\input.txt"
CALL opener (f$)
LET f$ = "docs\nul"
CALL opener (f$)
LET f$ = "\docs\nul"
CALL opener (f$)

LET f$ = "empty.tru"
CALL opener (f$)
LET f$ = "`Abdu'l-Bahá.txt"
CALL opener (f$)
END

TUSCRIPT

$$ MODE TUSCRIPT
file="input.txt",directory="docs"
IF (file=='file') THEN
PRINT file, " exists"
ELSE
PRINT/ERROR file," not exists"
ENDIF
IF (directory=='project') THEN
PRINT directory," exists"
ELSE
PRINT/ERROR "directory ",directory," not exists"
ENDIF
Output:
input.txt exists
@@@@@@@@  directory docs not exists                                    @@@@@@@@ 

UNIX Shell

test -f input.txt
test -f /input.txt
test -d docs
test -d /docs

The next program runs all four checks and prints the results.

for f in input.txt /input.txt; do
	test -f "$f" && r=true || r=false
	echo "$f is a regular file? $r"
done
for d in docs /docs; do
	test -d "$d" && r=true || r=false
	echo "$d is a directory? $r"
done

Ursa

The easiest way to do this in Ursa is to attempt to open the file in question. If it doesn't exist, an ioerror will be thrown.

def exists (string filename)
	decl file f
	try
		f.open filename
		return true
	catch ioerror
		return false
	end try
end exists

Vala

This needs to be compiled with the gio-2.0 package: valac --pkg gio-2.0 check_that_file_exists.vala

int main (string[] args) {
    string[] files = {"input.txt", "docs", Path.DIR_SEPARATOR_S + "input.txt", Path.DIR_SEPARATOR_S + "docs"};
    foreach (string f in files) {
        var file = File.new_for_path (f);
        print ("%s exists: %s\n", f, file.query_exists ().to_string ());
    }
    return 0;
}

A more complete version which informs whether the existing file is a regular file or a directory

int main (string[] args) {
    string[] files = {"input.txt", "docs", Path.DIR_SEPARATOR_S + "input.txt", Path.DIR_SEPARATOR_S + "docs"};
    foreach (var f in files) {
        var file = File.new_for_path (f);
        var exists = file.query_exists ();
        var name = "";
        if (!exists) {
            print ("%s does not exist\n", f);
        } else {
            var type = file.query_file_type (FileQueryInfoFlags.NOFOLLOW_SYMLINKS);
            if (type == 1) {
                name = "file";
            } else if (type == 2) {
                name = "directory";
            }
            print ("%s %s exists\n", name, f);
        }
    }
    return 0;
}

VBA

Option Explicit

Sub Main_File_Exists()
Dim myFile As String, myDirectory As String
    
    myFile = "Abdu'l-Bahá.txt"
    myDirectory = "C:\"
    Debug.Print File_Exists(myFile, myDirectory)
End Sub

Function File_Exists(F As String, D As String) As Boolean
    If F = "" Then
        File_Exists = False
    Else
        D = IIf(Right(D, 1) = "\", D, D & "\")
        File_Exists = (Dir(D & F) <> "")
    End If
End Function

VBScript

Set FSO = CreateObject("Scripting.FileSystemObject")

Function FileExists(strFile)
    If FSO.FileExists(strFile) Then
        FileExists = True
    Else
        FileExists = False
    End If
End Function
 
Function FolderExists(strFolder)
    If FSO.FolderExists(strFolder) Then
        FolderExists = True
    Else
        Folderexists = False
    End If
End Function
 
'''''Usage (apostrophes indicate comments-this section will not be run)'''''
'If FileExists("C:\test.txt") Then
'   MsgBox "It Exists!"
'Else
'   Msgbox "awww"
'End If
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

'Shorter version

If CreateObject("Scripting.FileSystemObject").FileExists("d:\test.txt") Then
    Wscript.Echo "File Exists"
Else
    Wscript.Echo "File Does Not Exist")
End If

Vedit macro language

Vedit allows using either '\' or '/' as directory separator character, it is automatically converted to the one used by the operating system.

// In current directory
if (File_Exist("input.txt")) { M("input.txt exists\n") } else { M("input.txt does not exist\n") }
if (File_Exist("docs/nul", NOERR)) { M("docs exists\n") } else { M("docs does not exist\n") }

// In the root directory
if (File_Exist("/input.txt")) { M("/input.txt exists\n") } else { M("/input.txt does not exist\n") }
if (File_Exist("/docs/nul", NOERR)) { M("/docs exists\n") } else { M("/docs does not exist\n") }

Visual Basic

Works with: Visual Basic version VB6 Standard

The proposed solutions for VBA and VBScript work in VB6 as well, however here's a Windows API based approach:

'declarations:
Public Declare Function GetFileAttributes Lib "kernel32" _
  Alias "GetFileAttributesA" (ByVal lpFileName As String) As Long
Public Const INVALID_FILE_ATTRIBUTES As Long = -1
Public Const ERROR_SHARING_VIOLATION As Long = 32&

'implementation:
Public Function FileExists(ByVal Filename As String) As Boolean
Dim l As Long
l = GetFileAttributes(Filename)
  If l <> INVALID_FILE_ATTRIBUTES Then
    FileExists = ((l And vbDirectory) = 0)
  ElseIf Err.LastDllError = ERROR_SHARING_VIOLATION Then
    FileExists = True
  End If
End Function

Visual Basic .NET

Platform: .NET

Works with: Visual Basic .NET version 9.0+
'Current Directory
Console.WriteLine(If(IO.Directory.Exists("docs"), "directory exists", "directory doesn't exists"))
Console.WriteLine(If(IO.Directory.Exists("output.txt"), "file exists", "file doesn't exists"))

'Root
Console.WriteLine(If(IO.Directory.Exists("\docs"), "directory exists", "directory doesn't exists"))
Console.WriteLine(If(IO.Directory.Exists("\output.txt"), "file exists", "file doesn't exists"))

'Root, platform independent
Console.WriteLine(If(IO.Directory.Exists(IO.Path.DirectorySeparatorChar & "docs"), _ 
   "directory exists", "directory doesn't exists"))
Console.WriteLine(If(IO.Directory.Exists(IO.Path.DirectorySeparatorChar & "output.txt"), _ 
  "file exists", "file doesn't exists"))

V (Vlang)

// Check file exists in V
// Tectonics: v run check-that-file-exists.v
module main
import os

// starts here
pub fn main() {
    // file and directory checks
    _ := os.execute("touch input.txt")
    println("os.is_file('input.txt'): ${os.is_file('input.txt')}")

    // make doc directory in current dir if it doesn't exist
    _ := os.execute("mkdir -p doc")
    println("os.is_dir('doc'): ${os.is_dir('doc')}")

    // check in the root dir
    println("os.is_file('/input.txt'): ${os.is_file('/input.txt')}")
    println("os.is_dir('/doc'): ${os.is_dir('/doc')}")

    // check for file, with empty file
    _ := os.execute("truncate -s 0 empty.txt")
    println("os.is_file('empty.txt'): ${os.is_file('empty.txt')}")

    // check for file, with exotic name
    wfn := "`Abdu'l-Bahá.txt"
    efn := wfn.replace_each(["'", r"\'", "`", r"\`"])
    _ := os.execute('touch $efn')
    println('os.is_file("$wfn"): ${os.is_file(wfn)}')
}
Output:
prompt$ v run check-that-file-exists.v
os.is_file('input.txt'): true
os.is_dir('doc'): true
os.is_file('/input.txt'): false
os.is_dir('/doc'): false
os.is_file('empty.txt'): true
os.is_file("`Abdu'l-Bahá.txt"): true

Wren

Empty files and directories have been created beforehand.

To check a file or directory exists in the root, just change "input.txt" to "/input.txt" and "docs" to "/docs" in the following script.

Since in Linux an empty directory has a size of 4K bytes, we check the number of files it contains to confirm that it's empty.

import "io" for Directory, File

for (name in ["input.txt", "`Abdu'l-Bahá.txt"]) {
    if (File.exists(name)) {
        System.print("%(name) file exists and has a size of %(File.size(name)) bytes.")
    } else {
        System.print("%(name) file does not exist.")
    }
}

var dir = "docs"
// if it exists get number of files it contains
if (Directory.exists(dir)) {
    var files = Directory.list(dir).count
    System.print("%(dir) directory exists and contains %(files) files.")
} else {
    System.print("%(dir) directory does not exist.")
}
Output:
input.txt file exists and has a size of 0 bytes.
`Abdu'l-Bahá.txt file exists and has a size of 0 bytes.
docs directory exists and contains 0 files.

XPL0

Attempting to open a non-existent file or directory will cause an error. A zero-length file is detected as existing.

int FD;         \file descriptor
[Trap(false);	\prevent errors from aborting program
FD:= FOpen("input.txt", 0);
if GetErr then Text(0, "input.txt doesn't exist^m^j");
FD:= FOpen("dir", 0);
if GetErr then Text(0, "dir doesn't exist^m^j");
FD:= FOpen("/input.txt", 0);
if GetErr then Text(0, "/input.txt doesn't exist^m^j");
FD:= FOpen("/dir", 0);
if GetErr then Text(0, "/dir doesn't exist^m^j");
]

Yabasic

open "foo.bar" for writing as #1
print #1 "Hallo !"
close #1
if (not open(1,"foo.bar")) print "Could not open 'foo.bar' for reading"
close #1
if (not open(1,"buzz.bar")) print "Could not open 'buzz.bar' for reading"

zkl

File.exists("input.txt")  //--> True (in this case a sym link)
File.exists("/input.txt") //-->False
File.isDir("/")     //-->True
File.isDir("docs")  //-->False
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