Hostname

From Rosetta Code
Task
Hostname
You are encouraged to solve this task according to the task description, using any language you may know.
Task

Find the name of the host on which the routine is running.

Ada

Works with GCC/GNAT

with Ada.Text_IO; use Ada.Text_IO;
with GNAT.Sockets;
 
procedure Demo is
begin
Put_Line (GNAT.Sockets.Host_Name);
end Demo;

ALGOL 68

Works with: ALGOL 68G version Any - tested with release mk15-0.8b.fc9.i386
Works with: POSIX version .1
STRING hostname;
get(read OF execve child pipe("/bin/hostname","hostname",""), hostname);
print(("hostname: ", hostname, new line))

Aikido

 
println (System.hostname)
 

AppleScript

 
host name of (system info)
 

AutoHotkey

MsgBox % A_ComputerName

via Windows Management Instrumentation (WMI)

for objItem in ComObjGet("winmgmts:\\.\root\CIMV2").ExecQuery("SELECT * FROM Win32_ComputerSystem")
MsgBox, % "Hostname:`t" objItem.Name

Arc

(system "hostname -f")

AWK

$ awk 'BEGIN{print ENVIRON["HOST"]}'
E51A08ZD

BaCon

PRINT "Hostname: ", HOSTNAME$

Batch File

Since Windows 2000 :

Hostname

BBC BASIC

      INSTALL @lib$+"SOCKLIB"
PROC_initsockets
PRINT "hostname: " FN_gethostname
PROC_exitsockets

C/C++

Works with: gcc version 4.0.1
Works with: POSIX version .1
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include <unistd.h>
 
int main(void)
{
char name[_POSIX_HOST_NAME_MAX + 1];
return gethostname(name, sizeof name) == -1 || printf("%s\n", name) < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}

C#

System.Net.Dns.GetHostName();

Caché ObjectScript

Write ##class(%SYS.System).GetNodeName()

Clojure

 
(.. java.net.InetAddress getLocalHost getHostName)
 
 
java -cp clojure.jar clojure.main -e "(.. java.net.InetAddress getLocalHost getHostName)"
 

COBOL

       identification division.
program-id. hostname.
 
data division.
working-storage section.
01 hostname pic x(256).
01 nullpos pic 999 value 1.
 
procedure division.
call "gethostname" using hostname by value length of hostname
string hostname delimited by low-value into hostname
with pointer nullpos
display "Host: " hostname(1 : nullpos - 1)
goback.
end program hostname.
 

CoffeeScript

 
os = require 'os'
console.log os.hostname()
 

Common Lisp

Another operating system feature that is implemented differently across lisp implementations. Here we show how to create a function that obtains the required result portably by working differently for each supported implementation. This technique is heavily used to make portable lisp libraries.

(defun get-host-name ()
#+(or sbcl ccl) (machine-instance)
#+clisp (let ((s (machine-instance))) (subseq s 0 (position #\Space s)))
#-(or sbcl ccl clisp) (error "get-host-name not implemented"))
Library: CFFI

Another way is to use the FFI to access POSIX' gethostname(2):

(cffi:defcfun ("gethostname" c-gethostname) :int
(buf :pointer) (len :unsigned-long))
 
(defun get-hostname ()
(cffi:with-foreign-object (buf :char 256)
(unless (zerop (c-gethostname buf 256))
(error "Can't get hostname"))
(values (cffi:foreign-string-to-lisp buf))))
BOA> (get-hostname)
"aurora"

D

import std.stdio, std.socket;
 
void main() {
writeln(Socket.hostName());
}

Delphi

program ShowHostName;
 
{$APPTYPE CONSOLE}
 
uses Windows;
 
var
lHostName: array[0..255] of char;
lBufferSize: DWORD;
begin
lBufferSize := 256;
if GetComputerName(lHostName, lBufferSize) then
Writeln(lHostName)
else
Writeln('error getting host name');
end.

E

makeCommand("hostname")()[0].trim()

Not exactly a good way to do it. A better way ought to be introduced along with a proper socket interface.

Emacs Lisp

(system-name)

F#

printfn "%s" (System.Net.Dns.GetHostName())

Factor

USE: io.sockets
host-name

Forth

Works with: GNU Forth version 0.7.0
include unix/socket.fs
 
hostname type

Erlang

Host = net_adm:localhost().

friendly interactive shell

Translation of: UNIX Shell
hostname

or

uname -n

Fortran

Works with: gfortran

The function/subroutine HOSTNM is a GNU extension.

program HostTest
character(len=128) :: name
call hostnm(name)
print *, name
end program HostTest

Using fortran 2003 C-interoperability we can call posix C function gethostname (unix system call) directly

 
program test_hostname
use, intrinsic :: iso_c_binding
implicit none
interface !to function: int gethostname(char *name, size_t namelen);
integer(c_int) function gethostname(name, namelen) bind(c)
use, intrinsic :: iso_c_binding, only: c_char, c_int, c_size_t
integer(c_size_t), value, intent(in) :: namelen
character(len=1,kind=c_char), dimension(namelen), intent(inout) :: name
end function gethostname
end interface
integer(c_int) :: status
integer,parameter :: HOST_NAME_MAX=255
character(kind=c_char,len=1),dimension(HOST_NAME_MAX) :: cstr_hostname
integer(c_size_t) :: lenstr
character(len=:),allocatable :: hostname
lenstr = HOST_NAME_MAX
status = gethostname(cstr_hostname, lenstr)
hostname = c_to_f_string(cstr_hostname)
write(*,*) hostname, len(hostname)
 
contains
! convert c_string to f_string
pure function c_to_f_string(c_string) result(f_string)
use, intrinsic :: iso_c_binding, only: c_char, c_null_char
character(kind=c_char,len=1), intent(in) :: c_string(:)
character(len=:), allocatable :: f_string
integer i, n
i = 1
do
if (c_string(i) == c_null_char) exit
i = i + 1
end do
n = i - 1 ! exclude c_null_char
allocate(character(len=n) :: f_string)
f_string = transfer(c_string(1:n), f_string)
end function c_to_f_string
 
end program test_hostname
 

FreeBASIC

' FB 1.05.0 Win64
 
' On Windows 10, the command line utility HOSTNAME.EXE prints the 'hostname' to the console.
' We can execute this remotely and read from its 'stdin' stream as follows:
 
Dim As String hostname
Open Pipe "hostname" For Input As #1
Input #1, hostname
Close #1
Print hostname
Print
Print "Press any key to quit"
Sleep

Gambas

Public Sub Main()
 
Print System.Host
 
End

Output:

charlie

Go

Use os.Hostname.

package main
 
import (
"fmt"
"os"
)
 
func main() {
fmt.Println(os.Hostname())
}

Groovy

println InetAddress.localHost.hostName

Harbour

? NetName()

Haskell

Library: network
import Network.BSD
main = do hostName <- getHostName
putStrLn hostName

Or if you don't want to depend on the network package being installed, you can implement it on your own (this implementation is based on the implementation in the network package).


module GetHostName where
 
import Foreign.Marshal.Array ( allocaArray0, peekArray0 )
import Foreign.C.Types ( CInt(..), CSize(..) )
import Foreign.C.String ( CString, peekCString )
import Foreign.C.Error ( throwErrnoIfMinus1_ )
 
getHostName :: IO String
getHostName = do
let size = 256
allocaArray0 size $ \ cstr -> do
throwErrnoIfMinus1_ "getHostName" $ c_gethostname cstr (fromIntegral size)
peekCString cstr
 
foreign import ccall "gethostname"
c_gethostname :: CString -> CSize -> IO CInt
 
main = do hostName <- getHostName
putStrLn hostName

Icon and Unicon

procedure main()
write(&host)
end

IDL

hostname = GETENV('computername')

J

NB. Load the socket libraries
 
load 'socket'
coinsert 'jsocket'
 
NB. fetch and implicitly display the hostname
 
> {: sdgethostname ''
 
NB. If fetching the hostname is the only reason for loading the socket libraries,
NB. and the hostname is fetched only once, then use a 'one-liner' to accomplish it:
 
> {: sdgethostname coinsert 'jsocket' [ load 'socket'

Java

import java.net.*;
class DiscoverHostName {
public static void main(final String[] args) {
try {
System.out.println(InetAddress.getLocalHost().getHostName());
} catch (UnknownHostException e) { // Doesn't actually happen, but Java requires it be handled.
}
}
}

JavaScript

Works with: JScript
var network = new ActiveXObject('WScript.Network');
var hostname = network.computerName;
WScript.echo(hostname);

Julia

 
println(gethostname())
 
Output:
harlan

Kotlin

// version 1.0.6
 
import java.net.InetAddress
 
fun main(args: Array<String>) {
println(InetAddress.getLocalHost().hostName)
}

Lasso

This will ge the hostname as reported by the web server

[web_request->httpHost]

-> www.myserver.com

This will ge the hostname as reported by the system OS

define host_name => thread {
 
data
public initiated::date, // when the thread was initiated. Most likely at Lasso server startup
private hostname::string // as reported by the servers hostname
 
public onCreate() => {
.reset
}
 
public reset() => {
if(lasso_version(-lassoplatform) >> 'Win') => {
protect => {
local(process = sys_process('cmd',(:'hostname.exe')))
#process -> wait
.hostname = string(#process -> readstring) -> trim&
#process -> close
}
else
protect => {
local(process = sys_process('/bin/hostname'))
#process -> wait
.hostname = string(#process -> readstring) -> trim&
#process -> close
}
}
.initiated = date(date -> format(`yyyyMMddHHmmss`)) // need to set format to get rid of nasty hidden fractions of seconds
.hostname -> size == 0 ? .hostname = 'undefined'
}
 
public asString() => .hostname
 
}
 
host_name

-> mymachine.local

LFE

 
(net_adm:localhost)
 

Liberty BASIC

lpBuffer$=Space$(128) + Chr$(0)
struct SIZE,sz As Long
SIZE.sz.struct=Len(lpBuffer$)
 
calldll #kernel32, "GetComputerNameA",lpBuffer$ as ptr, SIZE as struct, result as Long
CurrentComputerName$=Trim$(Left$(lpBuffer$, SIZE.sz.struct))
 
print CurrentComputerName$

Limbo

As with nearly anything in Inferno, it boils down to reading a file:

implement Hostname;
 
include "sys.m"; sys: Sys;
include "draw.m";
 
Hostname: module {
init: fn(nil: ref Draw->Context, nil: list of string);
};
 
init(nil: ref Draw->Context, nil: list of string)
{
sys = load Sys Sys->PATH;
buf := array[Sys->ATOMICIO] of byte;
 
fd := sys->open("/dev/sysname", Sys->OREAD);
if(fd == nil)
die("Couldn't open /dev/sysname");
 
n := sys->read(fd, buf, len buf - 1);
if(n < 1)
die("Couldn't read /dev/sysname");
 
buf[n++] = byte '\n';
sys->write(sys->fildes(1), buf, n);
}
 
die(s: string)
{
sys->fprint(sys->fildes(2), "hostname: %s: %r", s);
raise "fail:errors";
}
 

Sys->ATOMICIO is usually 8 kilobytes; this version truncates if you have a ridiculously long hostname.

Lingo

Library: Shell Xtra
 
sx = xtra("Shell").new()
if the platform contains "win" then
hostname = sx.shell_cmd("hostname", ["eol":RETURN]).line[1] -- win 7 or later
else
hostname = sx.shell_cmd("hostname", RETURN).line[1]
end if

LiveCode

answer the hostName

Lua

Requires: LuaSocket

socket = require "socket"
print( socket.dns.gethostname() )

Maple

Sockets:-GetHostName()

Mathematica / Wolfram Language

$MachineName

MATLAB

This is a built-in MATLAB function. "failed" is a Boolean which will be false if the command sent to the OS succeeds. "hostname" is a string containing the system's hostname, provided that the external command hostname exists.

[failed,hostname] = system('hostname')

mIRC Scripting Language

echo -ag $host

Modula-3

MODULE Hostname EXPORTS Main;
 
IMPORT IO, OSConfig;
 
BEGIN
IO.Put(OSConfig.HostName() & "\n");
END Hostname.

MUMPS

Write $Piece($System,":")

NetRexx

/* NetRexx */
options replace format comments java crossref savelog symbols binary
 
say InetAddress.getLocalHost.getHostName
 

NewLISP

(! "hostname")

Nim

import posix
const size = 64
var s = cstring(newString(size))
discard s.getHostname(size)
echo s

Oberon-2

Works with oo2c version 2

 
MODULE HostName;
IMPORT
OS:ProcessParameters,
Out;
BEGIN
Out.Object("Host: " + ProcessParameters.GetEnv("HOSTNAME"));Out.Ln
END HostName.
 

Output:

Host: localhost.localdomain

Objective-C

Cocoa / Cocoa Touch / GNUstep:

 
NSLog(@"%@", [[NSProcessInfo processInfo] hostName]);
 

Example Output:

 
2010-09-16 16:20:00.000 Playground[1319:a0f] sierra117.local // Hostname is sierra117.local.
 

Objeck

 
use Net;
 
bundle Default {
class Hello {
function : Main(args : String[]) ~ Nil {
TCPSocket->HostName()->PrintLine();
}
}
}
 

OCaml

Unix.gethostname()

Octave

Similarly to MATLAB, we could call system command hostname to know the hostname. But we can also call the internal function uname() which returns a structure holding several informations, among these the hostname (nodename):

uname().nodename

ooRexx

These solutions are platform specific.

Windows Platform

A solution using ActiveX/OLE on Windows

say .oleObject~new('WScript.Network')~computerName

and one using the Windows environment variables

say value('COMPUTERNAME',,'environment')

UNIX Platform

Some UNIX solutions (tested under Mac OS X):

ooRexx (and Rexx) can issue commands directly to the shell it's running under. Output of the shell commands will normally be STDOUT and STDERR. These next two samples will simply output the host name to the console if the program is run from a command prompt.

Note: The address command clause causes the contents of the literal string that follows it to be sent to the command shell.
address command 'hostname -f'
address command "echo $HOSTNAME"

Command output can also be captured by the program to allow further processing. ooRexx provides an external data queue manager (rxqueue) that can be used for this. In the following examples output written to STDOUT/STDERR is piped into rxqueue which sends it in turn to a Rexx queue for further processing by the program:

/* Rexx */
address command "echo $HOSTNAME | rxqueue"
address command "hostname -f | rxqueue"
loop q_ = 1 while queued() > 0
parse pull hn
say q_~right(2)':' hn
end q_
 

A utility class is also provided as a wrapper around the external data queue:

/* Rexx */
qq = .rexxqueue~new()
address command "echo $HOSTNAME | rxqueue"
address command "hostname -f | rxqueue"
loop q_ = 1 while qq~queued() > 0
hn = qq~pull()
say q_~right(2)':' hn
end q_
 

Oz

{System.showInfo {OS.getHostByName 'localhost'}.name}

PARI/GP

Running the hostname or uname program and capturing its output (the first line of output) in a string.

str = externstr("hostname")[1];
str = externstr("uname -n")[1];

Pascal

For Windows systems see the Delphi example. On Unix systems, FreePascal has the function GetHostName:

Program HostName;
 
uses
unix;
 
begin
writeln('The name of this computer is: ', GetHostName);
end.

Output example on Mac OS X:

The name of this computer is: MyComputer.local

Perl

Works with: Perl version 5.8.6
Library: Sys::HostnameHostname
use Sys::Hostname;
 
$name = hostname;

Perl 6

my $host = qx[hostname];

PHP

echo $_SERVER['HTTP_HOST'];
echo php_uname('n');
Works with: PHP version 5.3+
echo gethostname();

PicoLisp

This will just print the hostname:

(call 'hostname)

To use it as a string in a program:

(in '(hostname) (line T))

Pike

import System;
 
int main(){
write(gethostname() + "\n");
}

PL/SQL

SET serveroutput ON
BEGIN
DBMS_OUTPUT.PUT_LINE(UTL_INADDR.GET_HOST_NAME);
END;

Pop11

lvars host = sys_host_name();

PowerBASIC

This retreives the localhost's name:

HOST NAME TO hostname$

This attempts to retreive the name of an arbitrary machine on the network (assuming ipAddress& is valid):

HOST NAME ipAddress& TO hostname$

PowerShell

Windows systems have the ComputerName environment variable which can be used:

$Env:COMPUTERNAME

Also PowerShell can use .NET classes and methods:

[Net.Dns]::GetHostName()

PureBasic

Works with: PureBasic version 4.41
InitNetwork()
answer$=Hostname()

Python

Works with: Python version 2.5
import socket
host = socket.gethostname()

R

Sys.info provides information about the platform that R is running on. The following code returns the hostname as a string.

Sys.info()[["nodename"]]

Note that Sys.info isn't guaranteed to be available on all platforms. As an alternative, you can call an OS command.

system("hostname", intern = TRUE)

... or retrieve an environment variable

 
env_var <- ifelse(.Platform$OS.type == "windows", "COMPUTERNAME", "HOSTNAME")
Sys.getenv(env_var)
 

Racket

 
#lang racket/base
(require mzlib/os)
(gethostname)
 

REBOL

print system/network/host

REXX

REGINA and PC/REXX under most MS NT Windows

This REXX solution is for REGINA and PC/REXX under the Microsoft NT family of Windows (XP, Vista, 7, etc).
Other names could be used for the 3rd argument.

The   computername   is the same as the output for the   hostname.exe   program.

say value('COMPUTERNAME',,"ENVIRONMENT")
say value('OS',,"ENVIRONMENT")

output (using Windows/XP)

GERARD46
Windows_NT

R4 and ROO under most MS NT Windows

This REXX solution is for R4 and ROO under the Microsoft NT family of Windows (XP, Vista, 7, etc).
Other names could be used for the 3rd argument.

say value('COMPUTERNAME',,"SYSTEM")
say value('OS',,"SYSTEM")

MS DOS (without Windows), userid

Under Microsoft DOS (with no Windows), the closest thing to a name of a host would be the userid.

say userid()

MS DOS (without Windows), version of DOS

But perhaps the name or version of the MS DOS system would be more appropriate than the userid.

'VER'    /*this passes the  VER  command to the MS DOS system. */

Each REXX interpreter has their own name (some have multiple names) for the environmental variables.
Different operating systems may call their hostnames by different identifiers.
IBM mainframes (at one time) called the name of the host as a nodename and it needn't be
specified, in which case an asterisk (*) is returned.
I recall (perhaps wrongly) that Windows/95 and Windows/98 had a different environmental name for the name of the host.

UNIX Solution

This solution is platform specific and uses features that are available to the Regina implementation of Rexx.

Tested with Regina on Mac OS X. Should work on other UNIX/Linux distros.
/* Rexx */
address command "hostname -f" with output stem hn.
do q_ = 1 to hn.0
say hn.q_
end q_
exit

Ruby

require 'socket'
host = Socket.gethostname

Run BASIC

print Platform$    ' OS where Run BASIC is being hosted
print UserInfo$ ' Information about the user's web browser
print UserAddress$ ' IP address of the user

Scala

println(java.net.InetAddress.getLocalHost.getHostName)

Scheme

Works with: Chicken Scheme
(use posix)
(get-host-name)
Works with: Guile
(gethostname)

Seed7

The library socket.s7i defines the function getHostname, which returns the hostname.

$ include "seed7_05.s7i";
include "socket.s7i";
 
const proc: main is func
begin
writeln(getHostname);
end func;

Sidef

var sys = frequire('Sys::Hostname');
var host = sys.hostname;

Or:

var host = `hostname`.chomp;

Slate

Platform current nodeName

SNOBOL4

 
output = host(4,"HOSTNAME")
end

Standard ML

NetHostDB.getHostName ()

Smalltalk

Works with: Smalltalk/X
OperatingSystem getHostName

SQL

Works with: Oracle
 
SELECT host_name FROM v$instance;
 

Swift

Swift 3

print(ProcessInfo.processInfo.hostName)

Tcl

The basic introspection tool in TCL is the info command. It can be used to find out about the version of the current Tcl or Tk, the available commands and libraries, variables, functions, the level of recursive interpreter invocation, and, amongst a myriad other things, the name of the current machine:

set hname [info hostname]

Toka

2 import gethostname
1024 chars is-array foo
foo 1024 gethostname
foo type

TUSCRIPT

 
$$ MODE TUSCRIPT
host=HOST ()
 

UNIX Shell

hostname

or

uname -n

Ursa

out (ursa.net.localhost.name) endl console

Ursala

The user-defined hostname function ignores its argument and returns a string.

#import cli
 
hostname = ~&hmh+ (ask bash)/<>+ <'hostname'>!

For example, the following function returns the square root of its argument if it's running on host kremvax, but otherwise returns the square.

#import flo
 
creative_accounting = (hostname== 'kremvax')?(sqrt,sqr)

VBScript

 
Set objNetwork = CreateObject("WScript.Network")
WScript.Echo objNetwork.ComputerName
 

Vim Script

echo hostname()

zkl

System.hostname

Or open a server socket, which contains the hostname.

Network.TCPServerSocket.open(8080).hostname