File modification time

From Rosetta Code

This task will attempt to get and set the modification time of a file.

[edit] Ada

Ada does not allow you to change the date of a file but you can definitely read it:

with Ada.Directories;          use Ada.Directories;
with Ada.Text_IO;              use Ada.Text_IO;
with Ada.Calendar.Formatting;  use Ada.Calendar.Formatting;
 
procedure File_Time_Test is
begin
   Put_Line (Image (Modification_Time ("file_time_test.adb")));
end File_Time_Test;

[edit] AutoHotkey

FileGetTime, OutputVar, output.txt
MsgBox % OutputVar
FileSetTime, 20080101, output.txt
FileGetTime, OutputVar, output.txt
MsgBox % OutputVar

[edit] Batch File

Works with: Windows NT version 4

for %%f in (file.txt) do echo.%%~tf

The date/time format is dependent on the user's locale, like the contents of the %DATE% and %TIME% built-ins. There is no built-in way of setting a file's modification time.

[edit] C

POSIX:

#include <time.h>
#include <utime.h>
#include <sys/stat.h>
 
const char *filename = "input.txt";
 
int main() {
  struct stat foo;
  time_t mtime;
  struct utimbuf new_times;
 
  stat(filename, &foo);
  mtime = foo.st_mtime; /* seconds since the epoch */
 
  new_times.actime = foo.st_atime; /* keep atime unchanged */
  new_times.modtime = time(NULL);    /* set mtime to current time */
  utime(filename, &new_times);
 
  return 0;
}

[edit] C++

compiled with g++ -lboost_filesystem <sourcefile> -o <destination file>

#include <boost/filesystem/operations.hpp>
#include <ctime>
#include <iostream>
 
int main( int argc , char *argv[ ] ) {
   if ( argc != 2 ) {
      std::cerr << "Error! Syntax: moditime <filename>!\n" ;
      return 1 ;
   }
   boost::filesystem::path p( argv[ 1 ] ) ;
   if ( boost::filesystem::exists( p ) ) {
      std::time_t t = boost::filesystem::last_write_time( p ) ;
      std::cout << "On " << std::ctime( &t ) << " the file " << argv[ 1 ] 
	 << " was modified the last time!\n" ;
      std::cout << "Setting the modification time to now:\n" ;
      std::time_t n = std::time( 0 ) ;
      boost::filesystem::last_write_time( p , n ) ; 
      t = boost::filesystem::last_write_time( p ) ;
      std::cout << "Now the modification time is " << std::ctime( &t ) << std::endl ;
      return 0 ;
   } else {
      std::cout << "Could not find file " << argv[ 1 ] << '\n' ;
      return 2 ;
   }
}

[edit] C#

using System;
using System.IO;
 
Console.WriteLine(File.GetLastWriteTime("file.txt"));
File.SetLastWriteTime("file.txt", DateTime.Now);

[edit] Clojure

(import '(java.io File)
        '(java.util Date))
 
(Date. (.lastModified (File. "output.txt")))
(Date. (.lastModified (File. "docs")))
 
(.setLastModified (File. "output.txt")
                  (.lastModified (File. "docs")))

[edit] Common Lisp

Common Lisp doesn't provide a way to set the modification time. The write date can be accessed, however, using file-write-date:

(file-write-date "input.txt")

Implementations may, in addition, provide other ways of accessing these file attributes, e.g., POSIX bindings:

Works with: SBCL (1.0.30, OS X, Intel), Translation of: C

(sb-posix:utime takes an access time and a modification time rather than an array of two times.)

(let* ((filename "input.txt")
       (stat (sb-posix:stat filename))
       (mtime (sb-posix:stat-mtime stat)))
  (sb-posix:utime filename
		  (sb-posix:stat-atime stat)
		  (sb-posix:time)))

[edit] D

Works with: D version 2

import std.file: getTimes, setTimes, d_time;
 
void main() {
    d_time creation_time, access_time, modified_time;
    getTimes("data.txt", creation_time, access_time, modified_time);
    setTimes("data.txt", access_time, modified_time);
}

[edit] E

Works with: E-on-Java

Translation of: Java

E follows the Java File interface, except that it replaces boolean success/failure returns with an ejector parameter, so that the default behavior if the client does not handle the case is not to continue ignoring the failure.

def strdate(date) {
  return E.toString(<unsafe:java.util.makeDate>(date))
}
 
def test(type, file) {
    def t := file.lastModified()
    println(`The following $type called ${file.getPath()} ${
            if (t == 0) { "does not exist." } else { `was modified at ${strdate(t)}` }}`)
    println(`The following $type called ${file.getPath()} ${
            escape ne { file.setLastModified(timer.now(), ne); "was modified to current time." } catch _ { "does not exist." }}`)
    println(`The following $type called ${file.getPath()} ${
            escape ne { file.setLastModified(t, ne); "was modified to previous time." } catch _ { "does not exist." }}`)
}
 
test("file", <file:output.txt>)
test("directory", <file:docs>)

[edit] Factor

"foo.txt" file-info modified>> .

Setting the modified time is not cross-platform, so here's a Unix version.

USE: io.files.info.unix
 
"foo.txt" now 2 hours time+ set-file-modified-time

[edit] Go

package main
import "fmt"
import "os"
import "time"
 
var filename = "input.txt"
 
func main() {
  foo, _ := os.Stat(filename)
  fmt.Println(foo.Mtime_ns) // nanoseconds since the epoch
 
  os.Chtimes(filename,
             foo.Atime_ns,       // keep atime unchanged
             time.Nanoseconds()) // set mtime to current time
}

[edit] Haskell

import System.Posix.Files
import System.Posix.Time
 
do status <- getFileStatus filename
   let atime = accessTime status
       mtime = modificationTime status -- seconds since the epoch
   curTime <- epochTime
   setFileTimes filename atime curTime -- keep atime unchanged
                                       -- set mtime to current time

Alternative (only gets modification time):

import System.Directory
import System.Time
 
do ct <- getModificationTime filename
   cal <- toCalendarTime ct
   putStrLn (calendarTimeToString cal)

[edit] HicEst

CHARACTER timestamp*18
 
timestamp = ' ' ! blank timestamp will read:
SYSTEM(FIle="File_modification_time.hic", FileTime=timestamp) ! 20100320141940.525
 
timestamp = '19991231235950' ! set timestamp to Millenium - 10 seconds
SYSTEM(FIle="File_modification_time.hic", FileTime=timestamp)

[edit] Icon and Unicon

[edit] Icon

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

[edit] Unicon

 
every dir := !["./","/"] do {
   if i := stat(f := dir || "input.txt") then {
      write("info for ",f ," mtime= ",ctime(i.mtime),", atime=",ctime(i.ctime), ", atime=",ctime(i.atime)) 
      utime(f,i.atime,i.mtime-1024)
      i := stat(f)
      write("update for ",f ," mtime= ",ctime(i.mtime),", atime=",ctime(i.ctime), ", atime=",ctime(i.atime)) 
      }      
   else stop("failure to stat ",f)
   }

Notes:

Icon and Unicon accept both / and \ for directory separators.
'ctime' formats an integer representing an epoch time into human readable form
'utime' updates the atime and mtime values

[edit] J

The standard file access library only supports reading the file modification time.

   load 'files'
   fstamp 'input.txt'
2009 8 24 20 34 30

It is possible to set the time but it has to be done through OS specific external calls.

[edit] Java

import java.io.File;
import java.util.Date;
public class FileModificationTimeTest {
   public static void test(String type, File file) {
       long t = file.lastModified();
       System.out.println("The following " + type + " called " + file.getPath() +
            (t == 0 ? " does not exist." : " was modified at " + new Date(t).toString() )
       );
       System.out.println("The following " + type + " called " + file.getPath() + 
            (!file.setLastModified(System.currentTimeMillis()) ? " does not exist." : " was modified to current time." )
       );
       System.out.println("The following " + type + " called " + file.getPath() + 
            (!file.setLastModified(t) ? " does not exist." : " was modified to previous time." )
       );
   }
   public static void main(String args[]) {
       test("file", new File("output.txt"));
       test("directory", new File("docs"));
   }
}

[edit] JavaScript

Works with: JScript Get only.

var fso = new ActiveXObject("Scripting.FileSystemObject");
var f = fso.GetFile('input.txt');
var mtime = f.DateLastModified;

[edit] Mathematica

Get file modification time:

 FileDate["file","Modification"]

results is returned in format: {year,month,day,hour,minute,second}. Setting file modification time:

 SetFileDate["file",date,"Modification"]

where date is specified as {year,month,day,hour,minute,second}.

[edit] MAXScript

MAXScript has no method to set the mod time

-- Returns a string containing the mod date for the file, e.g. "1/29/99 1:52:05 PM"
getFileModDate "C:\myFile.txt"

[edit] Objective-C

NSFileManager *fm = [NSFileManager defaultManager];
 
NSLog(@"%@", [[fm fileAttributesAtPath:@"input.txt" traverseLink:YES] fileModificationDate]);
 
[fm changeFileAttributes:[NSDictionary dictionaryWithObject:[NSDate date] forKey:NSFileModificationDate]
                  atPath:@"input.txt"];

[edit] OCaml

#load "unix.cma";;
open Unix;;
let mtime = (stat filename).st_mtime;; (* seconds since the epoch *)
 
utimes filename (stat filename).st_atime (time ());;
(* keep atime unchanged
   set mtime to current time *)

[edit] Oz

Getting the modification time:

declare
  [Path] = {Module.link ['x-oz://system/os/Path.ozf']}
  Modified = {Path.mtime "input.txt"} %% posix time
in
  {Show {OsTime.localtime Modified}} %% human readable record

Setting the modification time is not possible, unless implemented as an extension in C or C++.

[edit] Perl

Works with: Perl version 5

my $mtime = (stat($file))[9]; # seconds since the epoch
 
# you should use the more legible version below:
use File::stat qw(stat);
my $mtime = stat($file)->mtime; # seconds since the epoch
 
utime(stat($file)->atime, time, $file);
# keep atime unchanged
# set mtime to current time

[edit] PHP

<?php
$filename = 'input.txt';
 
$mtime = filemtime($filename); // seconds since the epoch
 
touch($filename,
      time(), // set mtime to current time
      fileatime($filename)); // keep atime unchanged
?>

[edit] PicoLisp

(let File "test.file"
   (and
      (info File)
      (prinl (stamp (cadr @) (cddr @))) ) # Print date and time in UTC
   (call 'touch File) )                   # Set modification time to "now"

Output:

2010-02-20 15:46:37

[edit] Pop11

;;; Print modification time (seconds since Epoch)
sysmodtime('file') =>

[edit] PowerShell

$modificationTime = (Get-ChildItem file.txt).LastWriteTime
Set-ItemProperty file.txt LastWriteTime (Get-Date)

[edit] PureBasic

Debug FormatDate("%yyyy/%mm/%dd", GetFileDate("file.txt",#PB_Date_Modified))
  SetFileDate("file.txt",#PB_Date_Modified,Date(1987, 10, 23, 06, 43, 15))
Debug FormatDate("%yyyy/%mm/%dd - %hh:%ii:%ss", GetFileDate("file.txt",#PB_Date_Modified))

[edit] Python

import os
 
#Get modification time:
modtime = os.path.getmtime('filename')
 
#Set the access and modification times:
os.utime('path', (actime, mtime))
 
#Set just the modification time:
os.utime('path', (os.path.getatime('path'), mtime))
 
#Set the access and modification times to the current time:
os.utime('path', None)

[edit] R

See this R-devel mailing list thread for more information.

# Get the value
file.info(filename)$mtime
 
#To set the value, we need to rely on shell commands.  The following works under windows.
shell("copy /b /v filename +,,>nul")
# and on Unix (untested)
shell("touch -m filename")

[edit] RapidQ

name$ = DIR$("input.txt", 0)
PRINT "File date: "; FileRec.Date
PRINT "File time: "; FileRec.Time

[edit] Ruby

#Get modification time:
modtime = File.mtime('filename')
 
#Set the access and modification times:
File.utime(actime, mtime, 'path')
 
#Set just the modification time:
File.utime(File.atime('path'), mtime, 'path')
 
#Set the access and modification times to the current time:
File.utime(nil, nil, 'path')

[edit] Slate

Modifying the timestamp value is not currently a built-in feature. This code gets a raw value:

slate[1]> (File newNamed: 'LICENSE') fileInfo modificationTimestamp.
1240349799

[edit] Smalltalk

|a| 
a := File name: 'input.txt'.
(a lastModifyTime) printNl.

[edit] Standard ML

val mtime = OS.FileSys.modTime filename; (* returns a Time.time data structure *)
 
(* unfortunately it seems like you have to set modification & access times together *)
OS.FileSys.setTime (filename, NONE); (* sets modification & access time to now *)
(* equivalent to: *)
OS.FileSys.setTime (filename, SOME (Time.now ()))

[edit] Tcl

Assuming that the variable filename holds the name of the file...

# Get the modification time:
set timestamp [file mtime $filename]
 
# Set the modification time to ‘now’:
file mtime $filename [clock seconds]

[edit] Vedit macro language

Display file's last modification time as number of seconds since midnight.

Num_Type(File_Stamp_Time("input.txt"))

Displays file's last modification date and time as a string.

File_Stamp_String(10, "input.txt")
Reg_Type(10)

Vedit Macro Language has no method to set the modification time

[edit] Visual Basic .NET

Platform: .NET

Works with: Visual Basic .NET version 9.0+

Dim file As New IO.FileInfo("test.txt")
 
'Creation Time
Dim createTime = file.CreationTime
file.CreationTime = createTime.AddHours(1)
 
'Write Time
Dim writeTime = file.LastWriteTime
file.LastWriteTime = writeTime.AddHours(1)
 
'Access Time 
Dim accessTime = file.LastAccessTime
file.LastAccessTime = accessTime.AddHours(1)