Command-line arguments
You are encouraged to solve this task according to the task description, using any language you may know.
Retrieve the list of command-line arguments given to the program. For programs that only print the arguments when run directly, see Scripted main.
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
11l
:argv is a list containing all command line arguments, including the program name.
<lang 11l>:start:
print(‘Program name: ’:argv[0])
print("Arguments:\n":argv[1..].join("\n"))</lang>
8080 Assembly
This program runs under CP/M. CP/M includes some very rudimentary argument parsing: it assumes that the first two space-separated arguments are filenames. Apart from that you can get the raw command line, except that all lowercase letters are made uppercase.
If you need any further parsing, the program needs to do that by itself, which led to many people not bothering. (The CP/M assembler in particular is infamous for abusing the file extension to take arguments.) The following program shows everything CP/M gives it.
<lang 8080asm>putch: equ 2 ; CP/M syscall to print character puts: equ 9 ; CP/M syscall to print $-terminated string arglen: equ 80h ; Length of argument argmt: equ 81h ; Argument string fcb1: equ 5Ch ; FCBs fcb2: equ 6Ch org 100h ;;; Print all argument(s) as given lxi d,cmdln ; Print 'Command line: ' mvi c,puts call 5 lda arglen ; Retrieve the length of the argument lxi h,argmt ; Pointer to argument string call plstr ;;; CP/M also assumes that the first two words on the command ;;; line are filenames, and prepares two FCBs with the filenames ;;; in them. If there are no filenames, they will be blank. lxi d,file1 ; Print the first one mvi c,puts call 5 mvi a,11 ; Filenames are 8+3 characters long and padded with lxi h,fcb1+1 ; spaces call plstr lxi d,file2 ; Print the second one mvi c,puts call 5 mvi a,11 lxi h,fcb2+1 ; ... fall through - on small systems saving bytes is a virtue ;;; This subroutine prints a length-A string in HL. plstr: ana a ; If A=0, print nothing. rz push psw ; Save A and HL registers on the stack push h ; (CP/M syscalls clobber all registers) mov e,m ; Print character under HL mvi c,putch call 5 pop h ; Restore A and HL registers pop psw inx h ; Increment string pointer dcr a ; Decrement character counter jnz plstr ; Print next character if not zero ret cmdln: db 'Command line: $' file1: db 13,10,'File 1: $' file2: db 13,10,'File 2: $'</lang>
- Output:
A>args A>args Command line: File 1: File 2: A>args -c "alpha beta" -h "gamma" Command line: -C "ALPHA BETA" -H "GAMMA" File 1: -C File 2: "ALPHA A>args foobar.baz barbaz.qux Command line: FOOBAR.BAZ BARBAZ.QUX File 1: FOOBAR BAZ File 2: BARBAZ QUX
Ada
In Ada95 and later versions, command line arguments are available through the predefined package Ada.Command_Line. In Ada83, this would be implementation dependent.
<lang ada>with Ada.Command_line; use Ada.Command_Line; with Ada.Text_IO; use Ada.Text_IO;
procedure Print_Commands is begin
-- The number of command line arguments is retrieved from the function Argument_Count
-- The actual arguments are retrieved from the function Argument
-- The program name is retrieved from the function Command_Name
Put(Command_Name & " ");
for Arg in 1..Argument_Count loop
Put(Argument(Arg) & " ");
end loop;
New_Line;
end Print_Commands;</lang>
Alternative version using Matreshka
Uses Matreshka
<lang ada>with Ada.Wide_Wide_Text_IO;
with League.Application; with League.Strings;
procedure Main is begin
for J in 1 .. League.Application.Arguments.Length loop
Ada.Wide_Wide_Text_IO.Put_Line
(League.Application.Arguments.Element (J).To_Wide_Wide_String);
end loop;
end Main;</lang>
Aikido
The arguments are passed to the program as a vector of strings called args <lang aikido>
foreach arg in args {
println ("arg: " + arg)
}
</lang>
Aime
<lang aime>integer i;
i = 0; while (i < argc()) {
o_text(argv(i));
o_byte('\n');
i += 1;
}</lang>
ALGOL 68
<lang algol68>main:(
FOR i TO argc DO printf(($"the argument #"g(-0)" is "gl$, i, argv(i))) OD
)</lang> Linux command:
/usr/bin/a68g Command-line_arguments.a68 - 1 2 3 ...
Output:
the argument #1 is /usr/bin/a68g the argument #2 is ./Command-line_arguments.a68 the argument #3 is - the argument #4 is 1 the argument #5 is 2 the argument #6 is 3 the argument #7 is ...
Amazing Hopper
The main function "main(argv,argc)" is a macro-defined in HOPPER.H: get the arguments, and put them into array ARGV; ARGC have total arguments.
Macro MAIN(ARGV, ARGC):
<lang Amazing Hopper>
- defn main(_V_,_N_) #RAND, main:, V#RNDV=1,_V_={#VOID}, \
_N_=0,totalarg,mov(_N_), \
LOOPGETARG_#RNDV:, {[ V#RNDV ]},push(_V_),++V#RNDV,\
{_N_,V#RNDV},jle(LOOPGETARG_#RNDV),clear(V#RNDV)
</lang> VERSION 1: <lang Amazing Hopper>
- include <hopper.h>
main(argv, argc)
{"This program named: "},[1]get(argv),println
for(i=2, {i}lethan(argc),++i)
{"Argument #",i," = "}[i]get(argv),println
next
exit(0) </lang> VERSION 2: <lang Amazing Hopper>
- include <hopper.h>
main:
total arg, argc=0,mov(argc)
{"This program named: ",[&1]},println
i=2
__CNT_ARGS__:
{"Argumento #",i," = ",[&i]}println
++i,{argc,i}jle(__CNT_ARGS__)
exit(0) </lang> VERSION 3: <lang Amazing Hopper>
- include <hopper.h>
main(argv, argc)
i=2
#hl{
print( "This program named: ",argv[1],"\n")
while( i <= argc )
print("Argument #",i," = ",argv[i],"\n")
i += 1
wend
}
exit(0) </lang> VERSION 4: <lang Amazing Hopper>
- include <natural.h>
- include <hopper.h>
main:
get total arguments, and remember as (argc).
remember ("This program named: "),
remember ( argument (1) ), and print with a new line.
secondly, i=2,
do while ( variable (i) is less than (argc), \
consider this ( {"Argument #",i," = "} );\
remember ( argument (i) ) and print with a new line; finally ++i )
exit(0) </lang> ETCETERA...
- Output:
xu@MrDalien:~/Proyectos/xuesp/HOPPER$ hopper src/args1.com 1 "Rosseta code" 100 This program named: src/args1.com Argumento #2 = 1 Argumento #3 = Rosseta code Argumento #4 = 100
AppleScript
<lang applescript>
- !/usr/bin/env osascript
-- Print first argument on run argv
return (item 1 of argv)
end run </lang>
ARM Assembly
<lang ARM Assembly> /* ARM assembly Raspberry PI */ /* program commandLine.s */
/* Constantes */ .equ STDOUT, 1 @ Linux output console .equ EXIT, 1 @ Linux syscall .equ WRITE, 4 @ Linux syscall /* Initialized data */ .data szCarriageReturn: .asciz "\n"
/* UnInitialized data */ .bss .align 4
/* code section */ .text .global main main: @ entry of program
push {fp,lr} @ saves registers
add fp,sp,#8 @ fp <- start address
ldr r4,[fp] @ number of Command line arguments
add r5,fp,#4 @ first parameter address
mov r2,#0 @ init loop counter
loop:
ldr r0,[r5,r2,lsl #2] @ string address parameter bl affichageMess @ display string ldr r0,iAdrszCarriageReturn bl affichageMess @ display carriage return add r2,#1 @ increment counter cmp r2,r4 @ number parameters ? blt loop @ loop
100: @ standard end of the program
mov r0, #0 @ return code
pop {fp,lr} @restaur registers
mov r7, #EXIT @ request to exit program
swi 0 @ perform the system call
iAdrszCarriageReturn: .int szCarriageReturn
/******************************************************************/
/* display text with size calculation */
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
push {r0,r1,r2,r7,lr} @ save registres
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"
svc #0 @ call systeme
pop {r0,r1,r2,r7,lr} @ restaur 2 registres
bx lr @ return
</lang>
Arturo
<lang rebol>loop arg 'a [ print a ]</lang>
AutoHotkey
From the AutoHotkey documentation: "The script sees incoming parameters as the variables %1%, %2%, and so on. In addition, %0% contains the number of parameters passed (0 if none). " <lang autohotkey>Loop %0% ; number of parameters
params .= %A_Index% . A_Space
If params !=
MsgBox, %0% parameters were passed:`n`n %params%
Else
Run, %A_AhkPath% "%A_ScriptFullPath%" -c "\"alpha beta\"" -h "\"gamma\""</lang>
AWK
<lang awk>#!/usr/bin/awk -f
BEGIN {
print "There are " ARGC "command line parameters"
for(l=1; l<ARGC; l++) {
print "Argument " l " is " ARGV[l]
}
}</lang>
Babel
Invoke Babel in interactive mode with arguments using the -i switch:
<lang babel>babel -i Larry Mo Curly</lang>
Print the argv list with newlines:
<lang babel>argv prn !</lang>
- Output:
Larry Mo Curly
Print the argv list with spaces:
<lang babel>argv prs !</lang>
- Output:
Larry Mo Curly
To access an individual argument, use the ith operator to select an element from the argv list; print with newline using say:
<lang babel>argv 1 ith say !</lang>
- Output:
Mo
BASIC
For most older BASICs that supply the keyword COMMAND$, all arguments are returned in a single string that must then be parsed inside the program. (Unlike modern BASICs, there is often no easy way to retrieve the program's name.)
<lang qbasic>PRINT "args: '"; COMMAND$; "'"</lang>
Sample output:
args: 'This is a test.'
FreeBASIC supplies three ways to retrieve the arguments: COMMAND$ (which works identically to QuickBASIC's COMMAND$), COMMAND$() (a string array which works like C's argv[]), and __FB_ARGV__ (an array of pointers which works even more like C's argv[]) and __FB_ARGC__ (which works like C's argc).
<lang freebasic>DIM i AS INTEGER
PRINT COMMAND$
PRINT "This program is named "; COMMAND$(0) i = 1 DO WHILE(LEN(COMMAND$(i)))
PRINT "The argument "; i; " is "; COMMAND$(i) i = i + 1
LOOP
FOR i = 0 TO __FB_ARGC__ - 1
PRINT "arg "; i; " = '"; *__FB_ARGV__[i]; "'"
NEXT i</lang>
Sample output:
C:\>cla 1 2 3 1 2 3 This program is named cla The argument 1 is 1 The argument 2 is 2 The argument 3 is 3 arg 0 = 'cla' arg 1 = '1' arg 2 = '2' arg 3 = '3'
BaCon
<lang freebasic>' Command line arguments including program name PRINT "Entire command line: ", ARGUMENT$
SPLIT ARGUMENT$ BY " " TO cli$ SIZE args PRINT "Skip program name:"; FOR i = 1 TO args - 1
PRINT " " & cli$[i];
NEXT PRINT</lang>
- Output:
prompt$ bacon command-line.bac Converting 'command-line.bac'... done, 9 lines were processed in 0.002 seconds. Compiling 'command-line.bac'... cc -c command-line.bac.c cc -o command-line command-line.bac.o -lbacon -lm Done, program 'command-line' ready. prompt$ ./command-line -c "alpha beta" -h "gamma" Entire command line: ./command-line -c "alpha beta" -h gamma Skip program name: -c "alpha beta" -h gamma
Batch File
<lang dos>@echo off setlocal enabledelayedexpansion
set Count=0
- loop
if not "%1"=="" (
set /a count+=1 set parameter[!count!]=%1 shift goto loop
)
for /l %%a in (1,1,%count%) do (
echo !parameter[%%a]!
)</lang>
Another way of doing it
<lang dos>::args2.cmd @echo off setlocal enabledelayedexpansion set fn=%~f0 set p0=%~0 set p*=%* set /a c=1
- loop
if @%1==@ goto done set p%c%=%~1 set /a c=c+1 shift goto loop
- done
set /a c=c-1 set p#=%c% echo fn=%fn% echo p0=%p0% echo p*=%p*% echo p#=%p#% for /l %%i in (1,1,%p#%) do ( echo p%%i=!p%%i! )</lang>
Invocation:
<lang dos>>args2 foo "bar baz" quux fn=d:\bin\args2.cmd p0=args2 p*=foo "bar baz" quux p#=3 p1=foo p2=bar baz p3=quux </lang>
BBC BASIC
<lang bbcbasic>PRINT @cmd$</lang>
Bracmat
When Bracmat is started with one or more arguments, each argument is evaluated as if it were a Bracmat expression unless an argument (for example the first one) consumes the next argument(s) by calling arg$. Each invocation of arg$ pops one argument from the remaining list of arguments. Calling arg$ when no more arguments are available results in failure. The following program iterates over all arguments following the currently evaluated argument and outputs the argument to standard output.
<lang>whl'(arg$:?a&out$(str$("next arg=" !a)))</lang>
Now run Bracmat with this program as the first argument in a DOS environment:
bracmat "whl'(arg$:?a&out$(str$(\"next arg=\" !a)))" "a" /b -c 2+3 'd;' "out$(\"13+7=\" 13+7)"
Instead of starting in interactive mode, Bracmat interprets the first argument, which consumes all following arguments. This is output to standard output:
next arg=a
next arg=/b
next arg=-c
next arg=2+3
next arg='d;'
next arg=out$("13+7=" 13+7)
If given an argument index, arg$<arg index> returns the indexed argument without consuming any argument.
bracmat "0:?n&whl'(arg$!n:?a&out$str$(arg[ !n \"]=\" !a)&1+!n:?n)" "a" /b -c 2+3 'd;' "out$(\"13+7=\" 13+7)"
Output:
arg[0]=bracmat
arg[1]=0:?n&whl'(arg$!n:?a&out$str$(arg[ !n "]=" !a)&1+!n:?n)
arg[2]=a
arg[3]=/b
arg[4]=-c
arg[5]=2+3
arg[6]='d;'
arg[7]=out$("13+7=" 13+7)
13+7= 20
The last line demonstrates that not only the first argument is evaluated, but also the following arguments.
If Bracmat is run without arguments, Bracmat starts in interactive mode. In that situation calling arg$ fails. The same is true if Bracmat is compiled as a shared library (DLL or so).
C
Command line arguments are passed to main. Since the program name is also passed as "argument", the provided count is actually one more than the number of program arguments. Traditionally the argument count is named argc and the array of argument strings is called argv, but that's not mandatory; any (non-reserved) name will work just as well. It is, however, a good idea to stick to the conventional names.
Be careful on systems that use Unicode or other multibyte character sets. You may need to use a type of _wchar* and multi-byte-character-set-aware versions of printf.
<lang c>#include <stdlib.h>
- include <stdio.h>
int main(int argc, char* argv[]) {
int i;
(void) printf("This program is named %s.\n", argv[0]);
for (i = 1; i < argc; ++i)
(void) printf("the argument #%d is %s\n", i, argv[i]);
return EXIT_SUCCESS;
}</lang>
C#
There are at least two methods to access the command-line arguments. The first method is to access the string array passed to Main. This method only accesses the arguments and not the path to the executable. <lang csharp>using System;
namespace RosettaCode {
class Program {
static void Main(string[] args) {
for (int i = 0; i < args.Length; i++)
Console.WriteLine(String.Format("Argument {0} is '{1}'", i, args[i]));
}
}
}</lang>
The second method is to call the Environment.GetCommandLineArgs function. This method also returns the path to the executable as args[0] followed by the actual command line arguments. <lang csharp>using System;
namespace RosettaCode {
class Program {
static void Main() {
string[] args = Environment.GetCommandLineArgs();
for (int i = 0; i < args.Length; i++)
Console.WriteLine(String.Format("Argument {0} is '{1}'", i, args[i]));
}
}
}</lang>
C++
Command line arguments are passed the same way as in C.
This example uses iostream. Traditional C I/O also works.
<lang cpp>#include <iostream>
int main(int argc, char* argv[]) {
std::cout << "This program is named " << argv[0] << std::endl; std::cout << "There are " << argc-1 << " arguments given." << std::endl; for (int i = 1; i < argc; ++i) std::cout << "the argument #" << i << " is " << argv[i] << std::endl;
return 0;
}</lang>
Clean
getCommandLine from the module ArgEnv returns an array of command-line arguments (the first element is the name of the program).
<lang clean>import ArgEnv
Start = getCommandLine</lang>
Clojure
The value of *command-line-args* is a sequence of the supplied command line arguments, or nil if none were supplied.
<lang Clojure>(dorun (map println *command-line-args*))</lang>
CLU
While it is not part of the language standard as specified in the reference manual,
Portable CLU includes a library function get_argv which returns
all the arguments in order.
Note that unlike C, the program name itself is not included in the list of arguments.
<lang clu>% This program needs to be merged with PCLU's "useful.lib", % where get_argv lives. % % pclu -merge $CLUHOME/lib/useful.lib -compile cmdline.clu
start_up = proc ()
po: stream := stream$primary_output()
args: sequence[string] := get_argv()
for arg: string in sequence[string]$elements(args) do
stream$putl(po, "arg: " || arg)
end
end start_up</lang>
- Output:
$ ./cmdline -c "alpha beta" -h "gamma" arg: -c arg: alpha beta arg: -h arg: gamma
COBOL
The COBOL standard appears to say nothing regarding the retrieval of command-line arguments, although methods of retrieving them are provided by most vendors.
Getting the arguments in one go, exactly as they were passed in: <lang cobol> IDENTIFICATION DIVISION.
PROGRAM-ID. accept-all-args.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 args PIC X(50).
PROCEDURE DIVISION.
main-line.
ACCEPT args FROM COMMAND-LINE
DISPLAY args
GOBACK
.</lang>
Getting the arguments one at a time, with arguments being split by whitespace if not in quotes: <lang cobol> IDENTIFICATION DIVISION.
PROGRAM-ID. accept-args-one-at-a-time.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 arg PIC X(50) VALUE SPACES.
PROCEDURE DIVISION.
ACCEPT arg FROM ARGUMENT-VALUE
PERFORM UNTIL arg = SPACES
DISPLAY arg
MOVE SPACES TO arg
ACCEPT arg FROM ARGUMENT-VALUE
END-PERFORM
GOBACK
.</lang>
Passing arguments from UNIX/Linux Systems to COBOL.
<lang cobol>
*>Created By Zwiegnet 8/19/2004
IDENTIFICATION DIVISION.
PROGRAM-ID. arguments.
ENVIRONMENT DIVISION.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 command1 PIC X(50).
01 command2 PIC X(50).
01 command3 PIC X(50).
PROCEDURE DIVISION.
PERFORM GET-ARGS.
*> Display Usage for Failed Checks
ARGUSAGE.
display "Usage: <command1> <command2> <command3>"
STOP RUN.
*> Evaluate Arguments
GET-ARGS.
ACCEPT command1 FROM ARGUMENT-VALUE
IF command1 = SPACE OR LOW-VALUES THEN
PERFORM ARGUSAGE
ELSE
INSPECT command1 REPLACING ALL SPACES BY LOW-VALUES
ACCEPT command2 from ARGUMENT-VALUE
IF command2 = SPACE OR LOW-VALUES THEN
PERFORM ARGUSAGE
ELSE
INSPECT command2 REPLACING ALL SPACES BY LOW-VALUES
ACCEPT command3 from ARGUMENT-VALUE
IF command3 = SPACE OR LOW-VALUES THEN
PERFORM ARGUSAGE
ELSE
INSPECT command3 REPLACING ALL SPACES BY LOW-VALUES
*> Display Final Output
display command1 " " command2 " " command3
STOP RUN.
.</lang>
CoffeeScript
<lang coffeescript> console.log arg for arg in process.argv </lang>
Common Lisp
The Common Lisp standard does not specify anything relating to external invocation of a Common Lisp system. The method for getting command-line arguments varies by implementation.
The following function could be used to create a uniform way to access the arguments:
<lang lisp>(defun argv ()
(or #+clisp (ext:argv) #+sbcl sb-ext:*posix-argv* #+abcl ext:*command-line-argument-list* #+clozure (ccl::command-line-arguments) #+gcl si:*command-args* #+ecl (loop for i from 0 below (si:argc) collect (si:argv i)) #+cmu extensions:*command-line-strings* #+allegro (sys:command-line-arguments) #+lispworks sys:*line-arguments-list* nil))</lang>
D
<lang d>void main(in string[] args) {
import std.stdio;
foreach (immutable i, arg; args[1 .. $])
writefln("#%2d : %s", i + 1, arg);
}</lang>
Dart
<lang csharp>main(List<String> args) {
for(var arg in args)
print(arg);
}</lang>
DCL
case is not preserved unless the parameter is in quotes <lang DCL>$ i = 1 $ loop: $ write sys$output "the value of Pi' is ", p'i $ i = i + 1 $ if i .le. 8 then $ goto loop</lang>
- Output:
$ @command_line_arguments -c "alpha beta" -h "gamma" the value of P1 is -C the value of P2 is alpha beta the value of P3 is -H the value of P4 is gamma the value of P5 is the value of P6 is the value of P7 is the value of P8 is
Delphi
<lang delphi>// The program name and the directory it was called from are in // param[0] , so given the axample of myprogram -c "alpha beta" -h "gamma"
for x := 0 to paramcount do
writeln('param[',x,'] = ',param[x]);
// will yield ( assuming windows and the c drive as the only drive) :
// param[0] = c:\myprogram // param[1] = -c // param[2] = alpha beta // param[3] = -h // param[4] = gamma </lang>
Déjà Vu
Command line arguments are found in !args and !opts.
<lang dejavu>for i range 0 -- len !args: print\( "Argument #" i " is " ) . get-from !args i
if has !opts :c: !print "Ah, the -c option."
if has !opts :four: !. get-from !opts :four</lang>
- Output:
$ vu args-3.deja one two -c three --four=five Argument #0 is "args-3.deja" Argument #1 is "one" Argument #2 is "two" Argument #3 is "three" Ah, the -c option. "five"
The order of command line options is lost.
E
<lang e>interp.getArgs()</lang>
Eiffel
This class inherits functionality for dealing with command line arguments from class ARGUMENTS. It uses the feature separate_character_option_value to return the values by option name for each of the two arguments.
<lang eiffel >class
APPLICATION
inherit
ARGUMENTS
create
make
feature {NONE} -- Initialization
make
-- Print values for arguments with options 'c' and 'h'.
do
print ("Command line argument value for option 'c' is: ")
print (separate_character_option_value ('c') + "%N")
print ("Command line argument value for option 'h' is: ")
print (separate_character_option_value ('h') + "%N")
io.read_line -- Keep console window open
end
end</lang>
Output (for command line arguments: -c "alpha beta" -h "gamma"):
Command line argument value for option 'c' is: alpha beta Command line argument value for option 'h' is: gamma
Elena
ELENA 4.x : <lang elena>import system'routines; import extensions;
public program() {
program_arguments.forEvery:(int i)
{ console.printLine("Argument ",i," is ",program_arguments[i]) }
}</lang>
- Output:
Argument 0 is myprogram.exe Argument 1 is -c Argument 2 is alpha beta Argument 3 is -h Argument 4 is gamma
Elixir
Elixir provides command line arguments via the System.argv() function. <lang elixir>#!/usr/bin/env elixir IO.puts 'Arguments:' Enum.map(System.argv(),&IO.puts(&1))</lang> Example run: <lang bash>$ ./show-args.exs a b=2 --3 -4 Arguments: a b=2 --3 -4</lang>
Emacs Lisp
<lang emacslisp>
- !/usr/bin/env emacs --script
(dolist (arg command-line-args-left) (message arg)) </lang>
Erlang
When used as a script language the arguments is a list to the main/1 function. When compiled use init:get_arguments/0 <lang erlang>3> init:get_arguments().</lang> result <lang erlang>[{root,["/usr/erlang/erl5.5"]}, {progname,["erl"]}, {home,["/home/me"]}, {c,["alpha beta"]}, {h,["gamma"]}]</lang>
init:get_argument(name) can be used to fetch value of a particular flag
<lang erlang>4> init:get_argument(h). {ok,"gamma"} 5> init:get_argument(c). {ok,"alpha beta"}</lang>
Euphoria
<lang Euphoria>constant cmd = command_line() printf(1,"Interpreter/executable name: %s\n",{cmd[1]}) printf(1,"Program file name: %s\n",{cmd[2]}) if length(cmd)>2 then
puts(1,"Command line arguments:\n")
for i = 3 to length(cmd) do
printf(1,"#%d : %s\n",{i,cmd[i]})
end for
end if</lang>
F#
The entry-point function accepts the comment line arguments as an array of strings. The following program will print each argument on a separate line. <lang fsharp>#light [<EntryPoint>] let main args =
Array.iter (fun x -> printfn "%s" x) args 0</lang>
Factor
USING: io sequences command-line ; (command-line) [ print ] each
Fancy
<lang fancy>ARGV each: |a| {
a println # print each given command line argument
}</lang>
Fantom
<lang fantom> class Main {
public static Void main (Str[] args)
{
echo ("command-line args are: " + args)
}
} </lang>
Forth
Access to command line arguments is not a standard feature of Forth, since it is designed to be used without an operating system. The popular GNU implementation gforth runs from a shell and can access command line arguments similar to C: variable argc contains the count (including the command itself) and arg is a function that returns the nth argument as a string.
<lang forth>\ args.f: print each command line argument on a separate line
- main
argc @ 0 do i arg type cr loop ;
main bye</lang>
Here is output from a sample run. <lang forth>$ gforth args.f alpha "beta gamma" delta gforth args.f alpha beta gamma delta $</lang>
Fortran
<lang fortran>program command_line_arguments
implicit none integer, parameter :: len_max = 256 integer :: i , nargs character (len_max) :: arg nargs = command_argument_count() !nargs = iargc() do i = 0, nargs call get_command_argument (i, arg) !call getarg (i, arg) write (*, '(a)') trim (arg) end do
end program command_line_arguments
</lang>
Note: This sample uses the Fortran 2003 intrinsic routines command_argument_count and get_command_argument instead of the nonstandard extensions iargc and getarg. Most Fortran compilers support both.
Sample usage: <lang>> ./a.out -c "alpha beta" -h "gamma" ./a.out -c alpha beta -h gamma</lang>
FreeBASIC
<lang freebasic>' FB 1.05.0 Win64
' Program (myprogram.exe) invoke as follows: ' myprogram -c "alpha beta" -h "gamma"
Print "The program was invoked like this => "; Command(0) + " " + Command(-1) Print Print "Press any key to quit" Sleep</lang>
- Output:
The program was invoked like this => myprogram -c alpha beta -h gamma
Frink
Arguments to a program are available in the ARGS array variable.
<lang frink>
println[ARGS]
</lang>
FunL
<lang funl>println( args )</lang>
Gambas
Click this link to run this code <lang gambas>PUBLIC SUB main()
DIM l AS Integer DIM numparms AS Integer DIM parm AS String numparms = Application.Args.Count FOR l = 0 TO numparms - 1 parm = Application.Args[l] PRINT l; " : "; parm NEXT
END</lang>
Genie
<lang genie>[indent=4] /*
Command line arguments, in Genie
valac commandLine.gs ./commandLine sample arguments 'four in total here, including args 0'
- /
init
// Output the number of arguments print "%d command line argument(s):", args.length
// Enumerate all command line arguments
for s in args
print s
// to reiterate, args[0] is the command
if args[0] is not null
print "\nWith Genie, args[0] is the command: %s", args[0]</lang>
- Output:
prompt$ valac commandLine.gs prompt$ ./commandLine -c "alpha beta" -h "gamma" 5 command line argument(s): ./commandLine -c alpha beta -h gamma With Genie, args[0] is the command: ./commandLine
Global Script
Command-line arguments are passed to the main program as a linked list of strings (which are also linked lists).
This uses the gsio I/O operations, which are designed to be simple to implement on top of Haskell and simple to use. It also uses impmapM, which is a specific specialization of mapM for the HSGS implementation.
<lang Global Script>λ 'as. impmapM (λ 'a. print qq{Argument: §(a)\n}) as</lang>
Go
<lang go> package main import ( "fmt" "os" )
func main() { for i, x := range os.Args[1:] { fmt.Printf("the argument #%d is %s\n", i, x) } } </lang>
Groovy
Command-line arguments are accessible via the args list variable. The following is saved as the file "Echo.groovy": <lang groovy>println args</lang>
The existence of command-line arguments presupposes the existence of a command line interpreter. The following test runs were entered in a cygwin bash shell in a Microsoft Windows XP system:
$ groovy Echo this is an argument list [this, is, an, argument, list] $ groovy Echo -x alkfrew4oij -cdkjei +22 [-x, alkfrew4oij, -cdkjei, +22] $
For more sophisticated command-line option and option-argument parsing use the CliBuilder (command-line interface builder) library, which extends the functionality of the Java-based Apache Commons CLI library to Groovy.
Harbour
Uses the Harbour-specific hb_PValue() function <lang visualfoxpro>PROCEDURE Main()
LOCAL i
FOR i := 1 TO PCount()
? "argument", hb_ntos( i ), "=", hb_PValue( i )
NEXT
RETURN</lang>
Haskell
Defined by the System module, getArgs :: IO [String] provides the command-line arguments in a list.
myprog.hs: <lang haskell>import System main = getArgs >>= print</lang>
myprog a -h b c => ["a","-h","b","c"]
HicEst
<lang hicest>DO i = 2, 100 ! 1 is HicEst.exe
EDIT(Text=$CMD_LINE, SePaRators='-"', ITeM=i, IF ' ', EXit, ENDIF, Parse=cmd, GetPosition=position) IF(position > 0) WRITE(Messagebox) cmd
ENDDO</lang>
Icon and Unicon
Command line parameters are passed to Icon/Unicon programs as a list of strings. <lang Icon>procedure main(arglist) every write(!arglist) end</lang>
includes options that parses the command line as switches and arguments and returns the results in a table.
Io
<lang io>System args foreach(a, a println)</lang>
Ioke
<lang ioke>System programArguments each(println)</lang>
J
The global ARGV holds the command line arguments. Thus, a program to display them:
<lang J> ARGV</lang>
Java
<lang java>public class Arguments {
public static void main(String[] args) {
System.out.println("There are " + args.length + " arguments given.");
for(int i = 0; i < args.length; i++)
System.out.println("The argument #" + (i+1) + " is " + args[i] + " and is at index " + i);
}
}</lang>
For more sophisticated command-line option and option-argument parsing use the Apache Commons CLI (command-line interface) library.
JavaScript
<lang javascript>process.argv.forEach((val, index) => {
console.log(`${index}: ${val}`);
});</lang>
<lang javascript>var objArgs = WScript.Arguments; for (var i = 0; i < objArgs.length; i++)
WScript.Echo(objArgs.Item(i));</lang>
<lang javascript>import System; var argv:String[] = Environment.GetCommandLineArgs(); for (var i in argv)
print(argv[i]);</lang>
<lang javascript>for (var i = 0; i < arguments.length; i++)
print(arguments[i]);</lang>
jq
jq distinguishes between command-line arguments and command-line options.
Only the former are available programmatically.
Specifically, both named and positional command-line arguments are available in the global constant $ARGS, a JSON object, as follows:
$ARGS.positional contains an array of the positional arguments as JSON strings
$ARGS.names is a JSON object of giving the mapping of name to value.
For example, the invocation:
$ jq -n '$ARGS' --args a b
yields:<lang json>{
"positional": [
"a",
"b"
],
"named": {}
}</lang>
Arguments specified with --args are always read as JSON strings; arguments specified with --jsonargs are interpreted as JSON, as illustrated here:
$ jq -n '$ARGS' --argjson x 0 --jsonargs 0 '{"a":1}'
{
"positional": [
0,
{
"a": 1
}
],
"named": {
"x": 0
}
}
Jsish
<lang javascript>#!/usr/local/bin/jsish puts(Info.argv0()); puts(console.args);</lang>
- Output:
$ jsish command-line-arguments.jsi -c "alpha beta" -h "gamma" /home/btiffin/lang/jsish/command-line-arguments.jsi [ "-c", "alpha beta", "-h", "gamma" ]
Julia
Works when the Julia program is run as a file argument to julia.exe. <lang Julia>using Printf
prog = Base.basename(Base.source_path())
println(prog, "'s command-line arguments are:") for s in ARGS
println(" ", s)
end </lang>
- Output:
$ julia command_line_arguments.jl -c "alpha beta" -h "gamma"
command_line_arguments.jl's command-line arguments are:
-c
alpha beta
-h
gamma
Klong
Command line arguments (but not the program name itself) are bound to the variable ".a". The following program prints them, one argument per line:
<lang K> .p'.a </lang>
Kotlin
<lang scala>fun main(args: Array<String>) {
println("There are " + args.size + " arguments given.")
args.forEachIndexed { i, a -> println("The argument #${i+1} is $a and is at index $i") }
}</lang>
- Output:
See Java output.
Lasso
<lang lasso>#!/usr/bin/lasso9
iterate($argv) => {
stdoutnl("Argument " + loop_count + ": " + loop_value)
}</lang> Output: <lang shell>$ lasso9 arguments.lasso -c "alpha beta" -h "gamma" Argument 1: arguments.lasso Argument 2: -c Argument 3: alpha beta Argument 4: -h Argument 5: gamma</lang>
LFE
To demonstrate this, we can start the LFE REPL up with the parameters for this example: <lang shell> $ ./bin/lfe -pa ebin/ -c "alpha beta" -h "gamma" </lang>
Once we're in the shell, we can get all the initializing arguments with this call: <lang lisp> > (: init get_arguments) (#(root ("/opt/erlang/r15b03"))
#(progname ("erl"))
#(home ("/Users/oubiwann"))
#(user ("lfe_boot"))
#(pa ("ebin/"))
#(c ("alpha beta"))
#(h ("gamma")))
</lang>
We can also get specific arguments if we know their keys: <lang lisp> > (: init get_argument 'c)
- (ok (("alpha beta")))
> (: init get_argument 'h)
- (ok (("gamma")))
</lang>
Liberty BASIC
<lang lb>print CommandLine$</lang>
Lingo
<lang lingo>put the commandline -- "-c alpha beta -h gamma"</lang>
In latest versions of Mac OS X, the above approach doesn't work anymore. But there is a free "Xtra" (binary plugin/shared library) called "CommandLine Xtra" that works both in Windows and Mac OS X and returns the command-line parsed into a lingo list (array):
<lang lingo>put getCommandLineArgs() -- ["-c", "alpha beta", "-h", "gamma"]</lang>
Logo
If the command line to a logo script is written
logo file.logo - arg1 arg2 arg3
Then the arguments after the "-" are found in a list in variable :COMMAND.LINE <lang logo>show :COMMAND.LINE [arg1 arg2 arg3]</lang> Alternatively, make the first line of an executable logo script:
#! /usr/bin/logo -
to be able to invoke the script with arguments.
file.logo arg1 arg2 arg3
LSE64
<lang lse64>argc , nl # number of arguments (including command itself) 0 # argument dup arg dup 0 = || ,t 1 + repeat drop</lang>
Lua
The lua scripting language does not use argc and argv conventions for the command line parameters. Instead, the command line parameters to the main script are provided through the global table arg. The script name is placed into element zero of arg, and the script parameters go into the subsequent elements:
<lang lua>print( "Program name:", arg[0] )
print "Arguments:" for i = 1, #arg do
print( i," ", arg[i] )
end</lang>
M2000 Interpreter
function quote$("a") return "a" a string in ""
Arguments in command line maybe two kinds, in first part those three letters identifiers with + or - for switches for interpreter and the last part to executed before loading the actual script.
For this example we make a script, save to temporary directory, and call it passing arguments. We can use Win as shell substitute in M2000 environment, or the Use statement. Reading the shell statement Win we can see how the command line composed. We call the m2000.exe in the appdir$ (application directory, is the path to M2000.exe), and pass a string as a file with a path. That path will be the current path for the new start of m2000.exe the host for M2000 Interpreter (an activeX dll).
<lang M2000 Interpreter> Module Checkit {
Document a$ = {
Module Global A {
Show
Read a$="nothing", x=0
Print a$, x
A$=Key$
}
A: End
}
Dir temporary$
Save.doc a$, "program.gsb"
\\ open if gsb extension is register to m2000.exe
Win quote$(dir$+"program.gsb")
\\ +txt is a switch for interpreter to use string comparison as text (not binary)
\\ so we can send switches and commands before the program loading
Win appdir$+"m2000.exe", quote$(dir$+"program.gsb +txt : Data {Hello}, 100")
\\ no coma after name (we can use "program.gsb" for names with spaces)
Use program.gsb "From Use statement", 200
\\ delete file
Wait 5000
Dos "del "+quote$(dir$+"program.gsb");
\\ open directory
Rem : Win temporary$
} Checkit </lang>
Mathematica/Wolfram Language
myprogram: <lang Mathematica>#!/usr/local/bin/MathematicaScript -script $CommandLine</lang> Output:
{myprogram,-c,alpha beta,-h,gamma}
Mercury
<lang>
- - module cmd_line_args.
- - interface.
- - import_module io.
- - pred main(io::di, io::uo) is det.
- - implementation.
- - import_module int, list, string.
main(!IO) :-
io.progname("", ProgName, !IO),
io.format("This program is named %s.\n", [s(ProgName)], !IO),
io.command_line_arguments(Args, !IO),
list.foldl2(print_arg, Args, 1, _, !IO).
- - pred print_arg(string::in, int::in, int::out, io::di, io::uo) is det.
print_arg(Arg, ArgNum, ArgNum + 1, !IO) :-
io.format("the argument #%d is %s\n", [i(ArgNum), s(Arg)], !IO).
</lang>
min
<lang min>args</lang>
MMIX
<lang mmix>argv IS $1 argc IS $0 i IS $2
LOC #100
Main LOC @
SETL i,1 % i = 1
Loop CMP $3,argc,2 % argc < 2 ?
BN $3,1F % then jump to end
XOR $255,$255,$255 % clear $255
8ADDU $255,i,argv % i*8 + argv
LDOU $255,$255,0 % argv[i]
TRAP 0,Fputs,StdOut % write the argument
GETA $255,NewLine % add a newline
TRAP 0,Fputs,StdOut
INCL i,1 % increment index
SUB argc,argc,1 % argc--
BP argc,Loop % argc > 0? then Loop
1H LOC @
XOR $255,$255,$255 % exit(0)
TRAP 0,Halt,0
NewLine BYTE #a,0</lang>
Modula-2
<lang modula2>MODULE try;
FROM Arguments IMPORT GetArgs, ArgTable, GetEnv; FROM InOut IMPORT WriteCard, WriteLn, WriteString;
VAR count, item : SHORTCARD;
storage : ArgTable;
BEGIN
GetArgs (count, storage);
WriteString ('Count ='); WriteCard (count, 4); WriteLn;
item := 0;
REPEAT
WriteCard (item, 4);
WriteString (' : ');
WriteString (storage^ [item]^);
WriteLn;
INC (item)
UNTIL item = count
END try.</lang> Example: <lang Modula-2> jan@Beryllium:~/modula/test$ try jantje zag eens pruimen hangen Count = 6
0 : try 1 : jantje 2 : zag 3 : eens 4 : pruimen 5 : hangen
</lang>
Modula-3
Command line parameters are accessed using the Params module. <lang modula3>MODULE Args EXPORTS Main;
IMPORT IO, Params;
BEGIN
IO.Put(Params.Get(0) & "\n");
IF Params.Count > 1 THEN
FOR i := 1 TO Params.Count - 1 DO
IO.Put(Params.Get(i) & "\n");
END;
END;
END Args.</lang>
Output:
martin@thinkpad:~$ ./prog ./prog martin@thinkpad:~$ ./prog 10 ./prog 10 martin@thinkpad:~$ ./prog 10 20 ./prog 10 20
Nanoquery
<lang Nanoquery>// // command-line arguments //
// output all arguments for i in range(0, len(args) - 1) println args[i] end</lang>
- Output:
$ java -jar ../nanoquery-2.3_1700.jar -b cmdline.nq "alpha beta" -h "gamma" -b cmdline.nq alpha beta -h gamma
Neko
<lang actionscript>/* command line arguments, neko */ var argc = $asize($loader.args)
/* Display count and arguments, indexed from 0, no script name included */ $print("There are ", argc, " arguments\n")
var arg = 0 while arg < argc $print($loader.args[arg ++= 1], "\n")</lang>
- Output:
prompt$ nekoc command-line-arguments.neko prompt$ neko ./command-line-arguments.n -c "alpha beta" -h "gamma" There are 4 arguments -c alpha beta -h gamma
Nemerle
<lang Nemerle>using System; using System.Console;
module CLArgs {
Main(args : array[string]) : void
{
foreach (arg in args) Write($"$arg "); // using the array passed to Main(), everything after the program name
Write("\n");
def cl_args = Environment.GetCommandLineArgs(); // also gets program name
foreach (cl_arg in cl_args) Write($"$cl_arg ");
}
}</lang>
NetRexx
In a stand-alone application NetRexx places the command string passed to it in a variable called arg. <lang NetRexx>/* NetRexx */ -- sample arguments: -c "alpha beta" -h "gamma" say "program arguments:" arg </lang> Output:
program arguments: -c "alpha beta" -h "gamma"
Nim
<lang nim>import os echo "program name: ", getAppFilename() echo "Arguments:" for arg in commandLineParams():
echo arg</lang>
Oberon-2
<lang oberon2> MODULE CommandLineArguments; IMPORT
NPCT:Args, Out := NPCT:Console;
BEGIN
Out.String("Args number: ");Out.Int(Args.Number(),0);Out.Ln;
Out.String("0.- : ");Out.String(Args.AsString(0));Out.Ln;
Out.String("1.- : ");Out.String(Args.AsString(1));Out.Ln;
Out.String("2.- : ");Out.String(Args.AsString(2));Out.Ln;
Out.String("3.- : ");Out.String(Args.AsString(3));Out.Ln;
Out.String("4.-: ");Out.String(Args.AsString(4));Out.Ln
END CommandLineArguments. </lang>
- Output:
Args number: 5 0.- : bin/CommandLineArguments 1.- : -c 2.- : alpha beta 3.- : -h 4.-: gamma
Objeck
<lang objeck> class Line {
function : Main(args : String[]) ~ Nil {
each(i : args) {
args[i]->PrintLine();
};
}
} </lang>
Objective-C
In addition to the regular C mechanism of arguments to main(), Objective-C also has another way to get the arguments as string objects inside an array object: <lang objc>NSArray *args = [[NSProcessInfo processInfo] arguments]; NSLog(@"This program is named %@.", [args objectAtIndex:0]); NSLog(@"There are %d arguments.", [args count] - 1); for (i = 1; i < [args count]; ++i){
NSLog(@"the argument #%d is %@", i, [args objectAtIndex:i]);
}</lang>
OCaml
The program name is also passed as "argument", so the array length is actually one more than the number of program arguments.
<lang ocaml>let () =
Printf.printf "This program is named %s.\n" Sys.argv.(0); for i = 1 to Array.length Sys.argv - 1 do Printf.printf "the argument #%d is %s\n" i Sys.argv.(i) done</lang>
Using the Arg module
<lang ocaml>(* default values *) let somebool = ref false let somestr = ref "" let someint = ref 0
let usage = "usage: " ^ Sys.argv.(0) ^ " [-b] [-s string] [-d int]"
let speclist = [
("-b", Arg.Set somebool, ": set somebool to true");
("-s", Arg.Set_string somestr, ": what follows -s sets some string");
("-d", Arg.Set_int someint, ": some int parameter");
]
let () =
(* Read the arguments *)
Arg.parse
speclist
(fun x -> raise (Arg.Bad ("Bad argument : " ^ x)))
usage;
Printf.printf " %b %d '%s'\n" !somebool !someint !somestr;
- </lang>
% ocaml arg.ml --help usage: tmp.ml [-b] [-s string] [-d int] -b : set somebool to true -s : what follows -s sets some string -d : some int parameter --help Display this list of options % ocaml arg.ml -d 4 -b -s blabla true 4 'blabla' % ocaml arg.ml false 0 ''
Oforth
System.Args returns command line arguments.
All arguments that begin with "--" are not included into this list. The first argument is the program name, so this list is never empty.
<lang Oforth>System.Args println</lang>
Oz
Raw arguments
Like in C, but without the program name: <lang oz>functor import Application System define
ArgList = {Application.getArgs plain}
{ForAll ArgList System.showInfo}
{Application.exit 0}
end</lang>
Preprocessed arguments
<lang oz>functor import Application System define
ArgSpec =
record(
c(type:string single %% option "--c" expects a string, may only occur once,
optional:false char:&c) %% is not optional and has a shortcut "-c"
h(type:string single %% option "--h" expects a string, may only occur once,
default:"default h" %% is optional and has a default value if not given char:&h) %% and has a shortcut "-h"
)
Args = {Application.getArgs ArgSpec}
{System.showInfo Args.c}
{System.showInfo Args.h}
{Application.exit 0}
end</lang>
Pascal
Depends on implementation.
Perl
@ARGV is the array containing all command line parameters
<lang perl>my @params = @ARGV; my $params_size = @ARGV; my $second = $ARGV[1]; my $fifth = $ARGV[4];</lang>
If you don't mind importing a module:
<lang perl>use Getopt::Long; GetOptions (
'help|h' => \my $help, 'verbose|v' => \my $verbose,
);</lang>
Phix
constant cmd = command_line() ?cmd if cmd[1]=cmd[2] then printf(1,"Compiled executable name: %s\n",{cmd[1]}) else printf(1,"Interpreted (using %s) source name: %s\n",cmd[1..2]) end if if length(cmd)>2 then puts(1,"Command line arguments:\n") for i = 3 to length(cmd) do printf(1,"#%d : %s\n",{i,cmd[i]}) end for end if
When interpreting, the first two elements returned by command_line() are {interpreter,source}.
When compiled, the first two elements are instead {executable,executable}, so the parameters (if any) are consistently the 3rd element onwards.
- Output:
C:\Program Files (x86)\Phix>p testcl -c "alpha beta" -h "gamma"
{"C:\\Program Files (x86)\\Phix\\p.exe","C:\\Program Files (x86)\\Phix\\testcl.exw","-c","alpha beta","-h","gamma"}
Interpreted (using C:\Program Files (x86)\Phix\p.exe) source name: C:\Program Files (x86)\Phix\testcl.exw
Command line arguments:
#3 : -c
#4 : alpha beta
#5 : -h
#6 : gamma
C:\Program Files (x86)\Phix>p -c testcl -c "alpha beta" -h "gamma"
{"C:\\Program Files (x86)\\Phix\\testcl.exe","C:\\Program Files (x86)\\Phix\\testcl.exe","-c","alpha beta","-h","gamma"}
Compiled executable name: C:\Program Files (x86)\Phix\testcl.exe
Command line arguments:
#3 : -c
#4 : alpha beta
#5 : -h
#6 : gamma
C:\Program Files (x86)\Phix>testcl -c "alpha beta" -h "gamma"
{"C:\\Program Files (x86)\\Phix\\testcl.exe","C:\\Program Files (x86)\\Phix\\testcl.exe","-c","alpha beta","-h","gamma"}
Compiled executable name: C:\Program Files (x86)\Phix\testcl.exe
Command line arguments:
#3 : -c
#4 : alpha beta
#5 : -h
#6 : gamma
C:\Program Files (x86)\Phix>
PHP
When PHP is run from the command line, the special variables $argv and $argc contain the array of arguments, and the number of arguments, respectively. The program name is passed as the first argument.
<lang php><?php $program_name = $argv[0]; $second_arg = $argv[2]; $all_args_without_program_name = array_shift($argv); </lang>
PicoLisp
There are three ways to handle command-line arguments in PicoLisp:
1. Obtain all arguments as a list of strings via 'argv'
2. Fetch each argument individually with 'opt'
3. Use the built-in command-line interpretation, where arguments starting with a hyphen are executed as functions.
Here we use the third option, as it is not so obvious, sometimes more flexible, and in fact the most commonly used one for application development.
We define 'c' and 'h' as functions, which retrieve their argument with 'opt', and then 'load' all remaining command line arguments. <lang PicoLisp>#!/usr/bin/picolisp /usr/lib/picolisp/lib.l
(de c ()
(prinl "Got 'c': " (opt)) )
(de h ()
(prinl "Got 'h': " (opt)) )
(load T) (bye)</lang> Output:
$ ./myprogram -c "alpha beta" -h "gamma" Got 'c': alpha beta Got 'h': gamma
PL/I
<lang pli> /* The entire command line except the command word itself is passed */ /* to the parameter variable in PL/I. */ program: procedure (command_line) options (main);
declare command_line character (100) varying;
...
end program; </lang>
Pop11
variable poparglist contains list of command line arguments (as strings). One can use iteration over list to process then (for example print).
<lang pop11>lvars arg; for arg in poparglist do
printf(arg, '->%s<-\n');
endfor;</lang>
PowerBASIC
For versions of PowerBASIC prior to PB/Win 9 and PB/CC 5, the only option available is identical to the one used by QuickBASIC above: <lang powerbasic>? "args: '"; COMMAND$; "'"</lang>
Current versions of PowerBASIC (with the likely exception of PB/DOS) include COMMAND$() that works similarly to FreeBASIC's COMMAND$(), except that you can't retrieve the application's name:
<lang powerbasic>'these two both return ALL args
? COMMAND$
? COMMAND$(0)
DO WHILE(LEN(COMMAND$(i)))
PRINT "The argument "; i; " is "; COMMAND$(i) i = i + 1
LOOP</lang>
PowerShell
In PowerShell the arguments to a script can be accessed with the $args array:
<lang powershell>$i = 0
foreach ($s in $args) {
Write-Host Argument (++$i) is $s
}</lang>
Pure
Arguments are in global variables, argc and argv.
<lang pure> using system;
printf "There are %d command line argumants\n" argc; puts "They are " $$ map (puts) argv; </lang>
PureBasic
Reading all parameters
You can easily read all parameters by using ProgramParameter() without argument. <lang PureBasic>If OpenConsole()
Define n=CountProgramParameters()
PrintN("Reading all parameters")
While n
PrintN(ProgramParameter())
n-1
Wend
Print(#CRLF$+"Press Enter")
Input()
CloseConsole()
EndIf</lang>
Reading specific parameters
You can specify which parameter 'n' to read. <lang PureBasic>If OpenConsole()
Define n
PrintN("Reading specific pameters")
For n=0 To CountProgramParameters()
PrintN(ProgramParameter(n))
Next
Print(#CRLF$+"Press Enter")
Input()
CloseConsole()
EndIf</lang>
Python
sys.argv is a list containing all command line arguments, including the program name. Typically you slice the list to access the actual command line argument:
<lang python>import sys program_name = sys.argv[0] arguments = sys.argv[1:] count = len(arguments)</lang>
When running a module by invoking Python, the Python interpreter processes and removes some of the arguments, and the module cannot access them. To process command line arguments, run the module directly. sys.argv is a copy of the command line arguments; modifying sys.argv will not change the arguments seen by other processes, e.g. ps. (In other words sys.argv is an object which contains a copy of the process' command line arguments ... modifying that copy is only visible from within the Python program and not externally).
For powerful option parsing capabilities check out the optparse module.
R
Following adapted from this post by Forester:
Suppose you want to call your script test.r with the arguments a=1 b=c(2,5,6), where b is a numeric vector. Suppose you also want to redirect your output to test.out (not that you have a choice--I still don't know how to make R send shell-script output to stdout). You would then run
<lang R>R CMD BATCH --vanilla --slave '--args a=1 b=c(2,5,6)' test.r test.out</lang>
from the commandline, with the following text in test.r:
<lang R># Read the commandline arguments args <- (commandArgs(TRUE))
- args is now a list of character vectors
- First check to see if any arguments were passed,
- then evaluate each argument.
if (length(args)==0) {
print("No arguments supplied.")
# Supply default values
a <- 1
b <- c(1,1,1)
} else {
for (i in 1:length(args)) {
eval(parse(text=argsi))
}
} print(a*2) print(b*3)</lang>
(possibly preceding code that actually does something :-) Your output test.out would then contain (e.g., if you cat it)
[1] 2 [1] 6 15 18 > proc.time() user system elapsed 0.168 0.026 0.178
If you know how to get the output
- sent to stdout (i.e., as is normal with shell scripts)
- done without the profiling
please update this example!
Racket
The following is the simplest program that prints the command-line arguments:
<lang scheme>#lang racket (current-command-line-arguments)</lang>
You can also explicitly print each argument to standard output:
<lang scheme>#lang racket
(for ([arg (current-command-line-arguments)]) (displayln arg))</lang>
Raku
(formerly Perl 6)
Perl 5's @ARGV is available as @*ARGS. Alternatively, if you define a subroutine named MAIN, Perl will automatically process @*ARGS according to Unix conventions and MAIN's signature (or signatures, if your MAIN is a multi sub) and then call MAIN with appropriate arguments; see Synopsis 6 or [1].
<lang perl6># with arguments supplied $ raku -e 'sub MAIN($x, $y) { say $x + $y }' 3 5 8
- missing argument:
$ raku -e 'sub MAIN($x, $y) { say $x + $y }' 3 Usage: -e '...' x y</lang>
If the program is stored in a file, the file name is printed instead of -e '...'.
RapidQ
<lang rapidq>PRINT "This program is named "; Command$(0) FOR i=1 TO CommandCount
PRINT "The argument "; i; " is "; Command$(i)
NEXT i</lang>
Raven
<lang raven>ARGS print
stack (6 items)
0 => "raven" 1 => "myprogram" 2 => "-c" 3 => "alpha beta" 4 => "-h" 5 => "gamma"</lang>
REALbasic
<lang vb>Function Run(args() as String) As Integer
For each arg As String In args Stdout.WriteLine(arg) Next
End Function</lang> Output (given arguments: --foo !bar "bat bang"):
appName.exe --foo !bar bat bang
REXX
The entire command line arguments (as a single string) are passed by REXX to the program. <lang rexx>say 'command arguments:' say arg(1)</lang> Input:
myprogram -c "alpha beta" -b "gamma"
However, in the above example (as shown), it's suggested that (maybe) only options that start with a minus (-) are to be examined and assumed to be options. <lang rexx>parse arg aaa /*get the arguments. */
/*another version: */
/* aaa=arg(1) */
say 'command arguments:' say aaa
opts= /*placeholder for options. */ data= /*placeholder for data. */
do j=1 to words(aaa)
x=word(aaa,j)
if left(x,1)=='-' then opts=opts x /*Option? Then add to opts.*/
else data=data x /*Must be data. Add to data.*/
end
/*the above process adds a leading blank to OPTS and DATA*/
opts=strip(opts,'L') /*strip leading blanks. */ data=strip(data,'l') /*strip leading blanks. */ say say 'options='opts say ' data='data</lang>
- Note to users of Microsoft Windows and Regina REXX
Note that some REXX pass the command line as is, but Regina REXX lets the operating system parse it first (for instance Windows), and Windows will pass anything (along to the program being invoked) inside double quotes (") to the program as is. Any other data not in double quotes is passed as is.
Output from Regina REXX under Windows with the invocation:
myprogram -c "alpha beta" -h "gamma"
command arguments: -c alpha beta -h gamma options=-c -h data=alpha beta gamma
Output from others REXXes under Windows with the invocation:
myprogram -c "alpha beta" -h "gamma"
command arguments: -c "alpha beta" -h "gamma" options=-c -h data="alpha beta" "gamma"
- Notes to UNIX users
The rexx programming language does not preserve command line parameters containing spaces. This renders it unsuitable for use for wrapperscript applications, where filenames containing spaces need to be preserved, because there is no way to differentiate between a space within a parameter, and a space used to separate parameters.
- Scenario
If a script is called as follows:
ccwrapper "foo bar.c" "bar bar.c"
From the shell:
argv[0] = ccwrapper argv[1] = foo bar.c argv[2] = bar bar.c
It is a requirement of a wrapper that !argv[1] and !argv[2] are preserved when passed to the target application (a C compiler, in this example). Current implementations of rexx treat the command line arguments as one long argument:
arg() = 1 arg(1) = "foo bar.c bar bar.c"
The [parser] would separates the command line arguments by spaces. this results in !argv[1] and !argv[2] becoming split, so the target application would be called with different arguments:
argv[1] = foo argv[2] = bar.c argv[3] = bar argv[4] = bar.c
This has a different meaning to the compiler, so the arguments forwarded from rexx are rendered useless.
- Workaround
A workaround would be to create a wrapper around the rexx interpreter that encodes the command-line before calling rexx. The rexx application then decodes it. Some rexx interpreters, such as regina also provide a !-a switch as a workaround.
Ring
<lang ring> see copy("=",30) + nl see "Command Line Parameters" + nl see "Size : " + len(sysargv) + nl see sysargv see copy("=",30) + nl for x = 1 to len(sysargv)
see x + nl
next </lang>
Ruby
Command line arguments are available in the constant Object::ARGV.
myprog: <lang ruby>#! /usr/bin/env ruby p ARGV</lang>
myprog a -h b c => ["a","-h","b","c"]
Rust
<lang rust>use std::env;
fn main(){
let args: Vec<_> = env::args().collect();
println!("{:?}", args);
}</lang> Run: <lang>./program -c "alpha beta" -h "gamma" ["./program", "-c", "alpha beta", "-h", "gamma"]</lang>
S-lang
The command-line arguments exist in the array __argv: <lang S-lang>variable a; foreach a (__argv)
print(a);
</lang>Note 1: This array can be changed by calling
__set_argc_argv(new_argv);
Note 2: When a script is run as a parameter to slsh, __argv does not include slsh. __argv[0] is simply the name of the script.
The same is true if running a script via the editor jed, as in:
jed -script FILE [arg ...]
However, when [x/w]jed is entered normally, __argv consists of the command-line for the editor itself, with __argv[0] == jed or /path/to/jed or the equivalent.
Sather
<lang sather>class MAIN is
main(args:ARRAY{STR}) is
loop
#OUT + args.elt! + "\n";
end;
end;
end;</lang>
As in C (and others), the first element is the command itself (exactly as it is written in the command line and after shell variable expansion); e.g.
$ /home/home/rosetta/sather/a.out arg1 arg2 arg3
prints
/home/home/rosetta/sather/a.out arg1 arg2 arg3
Scala
Calling Scala from command line means invoking a method called main, defined on an
object, whose type is (Array[String]):Unit, meaning it receives an
array of strings, and returns unit. That array contains the command line arguments.
<lang scala>object CommandLineArguments extends App {
println(s"Received the following arguments: + ${args.mkString("", ", ", ".")}")
}</lang>
When running a Scala script, where the whole body is executed, the arguments get stored in an array of strings called argv:
<lang scala>println(s"Received the following arguments: + ${argv.mkString("", ", ", ".")}")</lang>
Scheme
<lang scheme> (define (main args)
(for-each (lambda (arg) (display arg) (newline)) args))</lang>
Seed7
<lang seed7>$ include "seed7_05.s7i";
const proc: main is func
local
var integer: i is 0;
begin
writeln("This program is named " <& name(PROGRAM) <& ".");
for i range 1 to length(argv(PROGRAM)) do
writeln("The argument #" <& i <& " is " <& argv(PROGRAM)[i]);
end for;
end func;</lang>
Sidef
Command line arguments are available in the ARGV array. <lang ruby>say ARGV;</lang>
- Output:
% myprog -c "alpha beta" -h "gamma" ['-c', 'alpha beta', '-h', 'gamma']
Slate
<lang slate>StartupArguments do: [| :arg | inform: arg]</lang>
Smalltalk
<lang smalltalk>(1 to: Smalltalk getArgc) do: [ :i |
(Smalltalk getArgv: i) displayNl
]</lang>
<lang smalltalk>Smalltalk commandLineArguments printCR. Smalltalk commandLineArguments do:[:each | each printCR]</lang>
Standard ML
<lang sml>print ("This program is named " ^ CommandLine.name () ^ ".\n"); val args = CommandLine.arguments (); Array.appi
(fn (i, x) => print ("the argument #" ^ Int.toString (i+1) ^ " is " ^ x ^ "\n"))
(Array.fromList args);</lang>
Swift
<lang swift>let args = Process.arguments println("This program is named \(args[0]).") println("There are \(args.count-1) arguments.") for i in 1..<args.count {
println("the argument #\(i) is \(args[i])")
}</lang>
Alternately:
<lang swift>println("This program is named \(String.fromCString(Process.unsafeArgv[0])!).") println("There are \(Process.argc-1) arguments.") for i in 1 ..< Int(Process.argc) {
println("the argument #\(i) is \(String.fromCString(Process.unsafeArgv[i])!)")
}</lang>
<lang swift>println("This program is named \(String.fromCString(C_ARGV[0])!).") println("There are \(C_ARGC-1) arguments.") for i in 1 ..< Int(C_ARGC) {
println("the argument #\(i) is \(String.fromCString(C_ARGV[i])!)")
}</lang>
Tailspin
<lang tailspin> $ARGS -> !OUT::write </lang>
- Output:
[-c, alpha beta, -h, gamma]
Tcl
The predefined global variable argc contains the number of arguments passed to the program after the script being executed, argv contains those arguments as a list. (The name of the script is in the argv0 global variable, and the name of the executable interpreter itself is returned by the command info nameofexecutable.) Retrieving the second argument might look something like this:
<lang tcl>if { $argc > 1 } {
puts [lindex $argv 1]
}</lang>
(Tcl counts from zero, thus [lindex $list 1] retrieves the second item in the list)
Toka
Arguments are stored into an array. The first element in the array is the name of the program, the rest are the arguments in order. The number of arguments is provided by #args.
<lang toka>[ arglist array.get type cr ] is show-arg [ dup . char: = emit space ] is #= 1 #args [ i #= show-arg ] countedLoop</lang>
TXR
Command line arguments in TXR's pattern-based extraction language can be treated as the lines of a text stream, which is arranged using the directive @(next :args). Thus TXR's text parsing capabilities work over the argument list.
This @(next :args) should be written as the first line of the TXR program, because TXR otherwise interprets the first argument as the name of an input file to open.
<lang txr>@(next :args) @(collect) @arg @(end) @(output) My args are: {@(rep)@arg, @(last)@arg@(end)} @(end)</lang>
$ ./txr args.txr
My args are: {}
$ ./txr args.txr 1
My args are: {1}
$ ./txr args.txr 1 2 3
My args are: {1, 2, 3}
Arguments are also available via two predefined variables: *full-args* and *args*, which are lists of strings, such that *args* is a suffic of *full-args*. *full-args* includes the arguments that were processed by TXR itself; *args* omits them.
Here is an example program which requires exactly three arguments. Note how ldiff is used to compute the arguments that are processed by TXR (the interpreter name, any special arguments and script name), to print an accurate usage message.
<lang txrlisp>(tree-case *args*
((a b c) (put-line "got three args, thanks!")) (else (put-line `usage: @(ldiff *full-args* *args*) <arg1> <arg2> <arg3>`)))</lang>
- Output:
$ txr command-line-args.txr 1 2 usage: txr command-line-args.txr <arg1> <arg2> <arg3> $ txr command-line-args.txr 1 2 3 4 usage: txr command-line-args.txr <arg1> <arg2> <arg3> $ txr command-line-args.txr 1 2 3 got three args, thanks!
UNIX Shell
Bourne Shell
To retrieve the entire list of arguments: <lang bash>WHOLELIST="$@"</lang> To retrieve the second and fifth arguments: <lang bash>SECOND=$2 FIFTH=$5</lang>
Ursa
In Ursa, all command line arguments (including the program name as invoked) are contained in the string stream args. <lang ursa>#
- command-line arguments
- output all arguments
for (decl int i) (< i (size args)) (inc i)
out args endl console
end for</lang>
Sample shell session in the Bourne shell:
$ ursa cmdlineargs.u "alpha beta" -h "gamma" cmdlineargs.u alpha beta -h gamma $
Ursala
Command line arguments are accessible to an application through a data structure initialized by the run-time system. This example application does nothing but display the data structure on standard output. <lang Ursala>#import std
- executable ('parameterized',)
clarg = <.file$[contents: --<>+ _option%LP]>+ ~command.options</lang> Here is a bash terminal session.
$ clarg -c alpha,beta -h gamma --foo=bar,baz
<
option[
keyword: 'c',
parameters: <'alpha','beta'>],
option[
position: 1,
keyword: 'h',
parameters: <'gamma'>],
option[
position: 2,
longform: true,
keyword: 'foo',
parameters: <'bar','baz'>]>V
The arguments to the program are stored in the stack,
args.v <lang v>$stack puts
./args.v a b c =[args.v a b c]</lang>
vbScript
<lang vbscript> 'Command line arguments can be accessed all together by
For Each arg In Wscript.Arguments
Wscript.Echo "arg=", arg
Next
'You can access only the named arguments such as /arg:value
For Each arg In Wscript.Arguments.Named
Wscript.Echo "name=", arg, "value=", Wscript.Arguments.Named(arg)
Next
'Or just the unnamed arguments
For Each arg In Wscript.Arguments.Unnamed
Wscript.Echo "arg=", arg
Next </lang>
Visual Basic
Like Qbasic, Visual Basic returns all of the args in the built-in variable Command$:
<lang vb>Sub Main
MsgBox Command$
End Sub</lang>
Visual Basic .NET
This syntax will tokenize the command line arguments. Tokens are normally delimited by spaces, but spaces can be part of a token if surrounded by quotes.
<lang vbnet>Sub Main(ByVal args As String())
For Each token In args
Console.WriteLine(token)
Next
End Sub</lang>
Wren
This assumes that the following script, myscript.wren, is run as follows: $ wren myscript.wren -c "alpha beta" -h "gamma" <lang ecmascript>import "os" for Process
System.print(Process.arguments)</lang>
- Output:
[-c, alpha beta, -h, gamma]
XPL0
Characters following the program name are copied into a buffer that is accessible as device 8. This displays the example command line with quote marks stripped off. <lang XPL0>int C; [loop [C:= ChIn(8);
if C = \EOF\$1A then quit;
ChOut(0, C);
];
CrLf(0); ]</lang>
- Output:
-c alpha beta -h gamma
zkl
File myprogram.zkl: <lang zkl>System.argv.println(); vm.arglist.println();</lang> zkl myprogram -c "alpha beta" -h "gamma"
- Output:
L("/home/craigd/Projects/ZKL/Bin/zkl","myprogram","-c","alpha beta","-h","gamma")
L("-c","alpha beta","-h","gamma")
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