Shell one-liner

From Rosetta Code
Shell one-liner
You are encouraged to solve this task according to the task description, using any language you may know.

Show how to specify and execute a short program in the language from a command shell, where the input to the command shell is only one line in length.

Avoid depending on the particular shell or operating system used as much as is reasonable; if the language has notable implementations which have different command argument syntax, or the systems those implementations run on have different styles of shells, it would be good to show multiple examples.


<lang bash>$ acl2 <<< '(cw "Hello.")'</lang>


Works with: gnat

under a unixoid shell (bash, sh, ...)

<lang bash>echo 'with Ada.text_IO; use Ada.text_IO; procedure X is begin Put("Hello!"); end X;' > x.adb; gnatmake x; ./x; rm x.adb x.ali x.o x</lang>

Note that this mercilessly overwrites and later deletes any files x.adb, x.ali, x,o and x in the current directory.


<lang aikido>echo 'println ("Hello")' | aikido</lang>


<lang sh>$ src/aime -c 'o_text("Hello, World!\n");'</lang>


Works with: ALGOL 68G version Any - tested with release mk15-0.8b.fc9.i386 - Interpret straight off

<lang bash>$ a68g -e 'print(("Hello",new line))'</lang> Output:

Works with: ELLA ALGOL 68 version Any - tested with release 1.8.8d.fc9.i386 - translate to C and then compile and run

For an ELLA ALGOL 68 one-liner, merge these lines of shell code: <lang bash>code='print(("Hello", new line))' a=/tmp/algol$$ s=/usr/share/algol68toc; echo -e "PROGRAM algol$$ CONTEXT VOID\nUSE standard\nBEGIN\n$code\nEND\nFINISH\n" > $a.a68 && a68toc -lib $s -dir $s -uname TMP -tmp $a.a68 && rm $a.a68 && gcc $s/Afirst.o $a.c -l{a68s,a68,m,c} -o $a && rm $a.c && $a; rm $a</lang> Output:



Maybe the most common way one can use awk is from the command line for one-liners, feeding the interpreter with an input. <lang bash>$ awk 'BEGIN { print "Hello"; }'</lang>

A more "complex" and "real" example: <lang bash>$ awk '/IN/ { print $2, $4; }' <input.txt</lang>

Select field 2 and 4 of lines matching the regular expression /IN/ (i.e. where IN appears)


The name of the BASIC executable will vary (common ones are basic, bas, and bwbasic), but in general, a short program can be piped to the interpreter like any other language: <lang bash>echo 'print "foo"'|basic</lang>

Note that under Windows (and presumably DOS) the two apostrophes (a.k.a. single quotes) should be omitted, since Windows doesn't remove them from the piped text (and the apostrophe is the comment character in many modern BASICs): <lang dos>echo print "foo"|basic</lang>

Also, some popular interpreters (including Michael Haardt's bas and Chipmunk Basic) will include an extra prompt before exiting unless you include exit or system (depending on the specific interpreter's syntax). This sample output shows both with and without system in bas:

erik@satan:~$ echo 'print "foo"'|bas
bas 2.2
Copyright 1999-2009 Michael Haardt.
This is free software with ABSOLUTELY NO WARRANTY.
> foo
> erik@satan:~$ echo 'print "foo":system'|bas
bas 2.2
Copyright 1999-2009 Michael Haardt.
This is free software with ABSOLUTELY NO WARRANTY.
> foo

Note that this is rather specific to Unix-like systems; most DOS and Windows interpreters are generally unable to handle programs in this manner, unless they were ported from a *nix system in the first place.

ZX Spectrum Basic

On the ZX Spectrum, the ROM basic allows direct commands to be entered from the system prompt:

<lang zxbasic>PRINT "Hello World!"</lang>


This example uses the predefined function tay to make a taylor expansion of e^x.

DOS: <lang bracmat>bracmat "put$tay$(e^x,x,20)&"</lang> Linux: <lang bracmat>bracmat 'put$tay$(e^x,x,10)&'</lang> Output:

+ x
+ 1/2*x^2
+ 1/6*x^3
+ 1/24*x^4
+ 1/120*x^5
+ 1/720*x^6
+ 1/5040*x^7
+ 1/40320*x^8
+ 1/362880*x^9
+ 1/3628800*x^10
+ 1/39916800*x^11
+ 1/479001600*x^12
+ 1/6227020800*x^13
+ 1/87178291200*x^14
+ 1/1307674368000*x^15
+ 1/20922789888000*x^16
+ 1/355687428096000*x^17
+ 1/6402373705728000*x^18
+ 1/121645100408832000*x^19
+ 1/2432902008176640000*x^20


<lang> Burlesque.exe --no-stdin "5 5 .+" </lang>

Using the official interpreter.


Works with: gcc

The following code leaves the file a.out in the current directory (it does not delete it to avoid to call another shell/system dependent command/program). The current directory is not specified by ./ in every system... <lang bash>$ echo 'main() {printf("Hello\n");}' | gcc -w -x c -; ./a.out</lang>


Note: whilst small, this is more than one line.

Requires PowerShell 2: <lang powershell>> Add-Type -TypeDefinition "public class HelloWorld { public static void SayHi() { System.Console.WriteLine(""Hi!""); } }" > [HelloWorld]::SayHi() Hi!</lang>


Note: whilst small, this is more than one line.

clj-env-dir comes with clojure-contrib.

<lang bash>$ clj-env-dir -e "(defn add2 [x] (inc (inc x))) (add2 40)"

  1. 'user/add2



This only works with Unix systems that have the device node /dev/stdin.

<lang bash>echo 'message(STATUS "Goodbye, World!")' | cmake -P /dev/stdin</lang>

Common Lisp

Varies by implementation

Works with: SBCL

<lang bash>sbcl --noinform --eval '(progn (princ "Hello") (terpri) (quit))'</lang>

Works with: CLISP

<lang bash>clisp.exe -q -x "(progn (format t \"Hello from CLISP\") (quit))"</lang>


Works with: D version 2

requires rdmd <lang d>rdmd --eval="writeln(q{Hello World!})"</lang>

Hello World!


<lang bash>dc -e '22 7/p'</lang>


<lang bash>rune --src.e 'println("Hello")'</lang>

The --src option ends with the the filename extension the provided type of program would have:

<lang>rune --src.e-awt 'def f := <swing:makeJFrame>("Hello");; f.addWindowListener(def _{to windowClosing(_) {interp.continueAtTop()} match _{}}); interp.blockAtTop()'</lang>

Emacs Lisp

<lang bash>emacs -batch -eval '(princ "Hello World!\n")' </lang> Or another example that does something useful: indent a C source file: <lang bash>emacs -batch sample.c --eval '(indent-region (point-min) (point-max) nil)' -f save-buffer</lang>


Erlang always starts other applications that can run in parallel in the background, and as such will not die by itself. To kill erl, we sequentially run the 'halt' function from the 'erlang' module (the -S is there to guarantee 'halt' will be evaluated after the io function). <lang bash>$ erl -noshell -eval 'io:format("hello~n").' -s erlang halt hello</lang>


<lang cmd>> echo printfn "Hello from F#" | fsi --quiet Hello from F#</lang>


<lang bash>$ factor -run=none -e="USE: io \"hi\" print"</lang>


Works with: GNU Forth

<lang bash>$ gforth -e ".( Hello) cr bye" Hello</lang>


This example, stolen from the c example is subject to the same caveats. While contrived, FORTRAN as a one liner can easily handle some unique tasks. Let's plot a Bessel function: <lang bash> $ gawk 'BEGIN{print"write(6,\"(2(g12.3,x))\")(i/10.0,besj1(i/10.0), i=0,1000)\nend";exit(0)}'|gfortran -ffree-form -x f95 - | gnuplot -p -e 'plot "<./a.out" t "Bessel function of 1st kind" w l' </lang> Sorry, I don't know how to upload my jpeg file for the Image tag. Let's use the dumb display instead.

  0.6 +*------------+-------------+------------+-------------+------------++
      +**           +             +     Bessel function of 1st kind ****** +
  0.5 +**                                                                 ++
      |**                                                                  |
  0.4 +**                                                                 ++
      * *                                                                  |
  0.3 *+*   *                                                             ++
      * *  **   *                                                          |
  0.2 *+*  ***  **  **                                                    ++
  0.1 *+*  * *  **  **  ***  **  **   *   **   *                          ++
      * ** * * ***  **  * * ***  **  ***  **  **  ***  **  **  ***  **  ** |
    0 *+ * * * * *  * * * * * *  *** * * * *  *** * * ***  *** * * ***  ***+
      |  * * * * ***  * * * * ***  * * * * ***  *** * * **** *** *** ***  *|
 -0.1 ++ * * * *  **  *** ***  **  **  ***  **  **   **  **  **   **  **  **
      |  *** ***  **  **   **  **   *   *                                  |
 -0.2 ++ **   **  **                                                      ++
      |  **   *                                                            |
 -0.3 ++ **                                                               ++
      +  **         +             +            +             +             +
 -0.4 ++------------+-------------+------------+-------------+------------++
      0             20            40           60            80           100


<lang bash>$ gema -p '\B=Hello\n@end' Hello</lang>


Go is first of all a compiled language and currently comes with no support for running as a script language. The compiler and linker can of course be run from a command line shell, as in, <lang bash>echo 'package main;func main(){println("hllowrld")}'>8.go;8g 8.go;8l 8.8;8.out</lang> This will overwrite existing files in the current directory 8.go, 8.8, and 8.out, assuming of course, that the the current directory is even writable, and will leave these files behind after executing.

Running Go as a script language is a popular request however, and one of the better solutions currently is gorun. Gorun has solutions for the temporary file problem, writing to best-guess temporary directories by default and having an option to specify the location when this is needed or desired. Gorun still expects to read the source code from a file however, so you are on your own to deal with this before passing the file to gorun. Example, <lang bash>echo 'package main;func main(){println("hllowrld")}'>/tmp/8.go;gorun /tmp/8.go</lang> Output from either example:



Works with: UNIX Shell

<lang bash>$ groovysh -q "println 'Hello'" Hello</lang>

<lang cmd>C:\Users\user> groovysh -q "println 'Hello'" Hello</lang>


<lang bash>$ ghc -e 'putStrLn "Hello"' Hello</lang>

Icon and Unicon

These examples work with posix shells.

<lang icon>echo "procedure main();write(\"hello\");end" | icont - -x</lang>

<lang unicon>echo "procedure main();write(\"hello world\");end" >hello.icn; unicon hello.icn -x</lang>


<lang bash>$ jconsole -js "exit echo 'Hello'" Hello</lang>

That said, note that J interpreters can themselves be thought of as command shells.


Works with: bash

These three lines work with Bourne Shell (or compatible) or C Shell (or compatible), or bash on Unix/Linux/MacOSX/Windows+cygwin

<lang bash>$ echo 'public class X{public static void main(String[]args){' \ > 'System.out.println("Hello Java!");}}' > $ javac && java X</lang>

A user can also enter this as one (very long) line:

<lang bash>$ echo 'public class X{public static void main(String[]args){System.out.println("Hello Java!");}}'>;javac X</lang>

Works with: MS-DOS

Works with cmd.exe on Windows (tested on Microsoft Windows XP [Version 5.1.2600]) <lang cmd>C:\>echo public class X{public static void main(String[] args){System.out.println("Hello Java!");}}> X Hello Java!</lang>


Works with: SpiderMonkey

<lang bash>$ js -e 'print("hello")' hello</lang>


<lang bash>lua -e 'print "Hello World!"'</lang>


Works with: Kona

<lang bash>$ k -e "\`0: \"hello\\n\""</lang>


<lang julia>$ julia -e 'for x in ARGS; println(x); end' foo bar foo bar</lang>


From stdin:

<lang Lasso>echo " 'The date and time is: ' + date " | lasso9 --</lang>

Or alternatively:

<lang Lasso>$ lasso9 -s " 'The date and time is: ' + date "</lang>

Liberty BASIC

<lang lb> echo print "hello">oneLiner.bas & liberty -r oneLiner.bas echo print "hello">oneLiner.bas & liberty -r oneLiner.bas </lang>


<lang Mathematica>echo Print[2+2] > file & math.exe -script file</lang>


Works with: UNIX Shell

Create a temporary file, execute the file via the NetRexx interpreter then delete the temporary file and any files generated via the translation. (i.e. Java class files etc.) <lang bash> $ TNRX=`mktemp T_XXXXXXXXXXXX` && test ! -e $TNRX.* && (echo 'say "Goodbye, World!"' >$TNRX; nrc -exec $TNRX; rm $TNRX $TNRX.*; unset TNRX) </lang>


NetRexx portable processor, version NetRexx 3.01, build 40-20120823-0156
Copyright (c) RexxLA, 2011,2012.  All rights reserved.
Parts Copyright (c) IBM Corporation, 1995,2008.
Program T_dO7RQs5HPElq
===== Exec: T_dO7RQs5HPElq =====
Goodbye, World!
Processing of 'T_dO7RQs5HPElq' complete


<lang NewLISP>newlisp -e "\"Hello\" ->"Hello"</lang>


Works with: UNIX Shell

<lang bash>./obc -run '"Hello"->PrintLine();' -dest hello.obe ; ./obr hello.obe</lang>


<lang bash>$ ocaml <(echo 'print_endline "Hello"') Hello</lang>


<lang matlab>$ octave --eval 'printf("Hello World, it is %s!\n",datestr(now));' Hello World, it is 28-Aug-2013 17:53:47!</lang>


<lang bash> rexx -e "say 'Goodbye, world.'" </lang>


This is difficult to do in Oz because the compiler/interpreter always wants the source code in a file and does not read from stdin. We can do somethings like this on Unix-like systems: <lang bash>echo >tmp.oz "{ hello}"; ozc -l System -e tmp.oz hello</lang>

With -l System we make the System module available so that we can print something.


<lang bash>echo "print(Pi)" | gp -q</lang>


<lang bash>$ echo "begin writeln('Hello World') end." >OneLiner.pas; fpc -Fe/dev/null OneLiner.pas; ./OneLiner Hello World</lang>


<lang bash>$ perl -e 'print "Hello\n"' Hello</lang>

More information about the many ways of invoking perl can be found in perlrun.

Perl 6

Works with: Rakudo version #22 "Thousand Oaks"

<lang bash>$ perl6 -e 'say "Hello, world!"' Hello, world!</lang>


assuming you have the PHP CLI (command-line interface) installed, not just the web server plugin <lang bash>$ php -r 'echo "Hello\n";' Hello</lang>


<lang PicoLisp>$ picolisp -'prinl "Hello world!"' -bye Hello world!</lang>


<lang bash>$ pike -e 'write("Hello\n");' Hello</lang>


<lang cmd>> powershell -Command "Write-Host 'Hello'" Hello</lang>


Runs on Linux with(thanks to) bash. Path variables must be set as decribed in INSTALL. <lang bash>$ echo 'messagerequester("Greetings","hello")' > "dib.pb" && ./pbcompiler dib.pb -e "dib" && ./dib</lang>


Prints "Hello"

<lang bash>$ python -c 'print "Hello"' Hello</lang>

Web server with CGI

The python CGIHTTPServer module is also an executable library that performs as a web server with CGI. to start enter: <lang bash>python -m CGIHTTPServer</lang> It returns with:

Serving HTTP on port 8000 ...


<lang bash>$ echo 'cat("Hello\n")' | R --slave Hello</lang>

Alternatively, using the Rscript front-end, <lang bash>$ Rscript -e 'cat("Hello\n")' Hello</lang>


<lang bash>$ racket -e "(displayln \"Hello World\")" Hello World</lang>


<lang bash>rebview -vswq --do "print {Hello!} quit" </lang>




<lang Retro>echo '"hello\n" puts bye' | ./retro</lang>


Note: "Regina" is the only version of REXX that supports this type of behavior (taking it's input from a console stream). <lang rexx> ┌────────────────────────────────────────────────┐

│  from the MS Windows® command line  (cmd.exe)  │

echo do j=10 by 20 for 4;say right('hello',j);end | regina</lang> output when using the (above) from the command line:



From Unix: <lang bash>$ ruby -e 'puts "Hello"' Hello</lang>

Works with: JRuby

<lang bash>$ jruby -e 'puts "Hello from JRuby"' Hello from JRuby</lang>

Works with: Rubinius

<lang bash>$ rbx -e 'puts "Hello from Rubinius"' Hello from Rubinius</lang>


<lang bash>print shell$("echo hello world")</lang>


Library: Scala

<lang cmd>C:\>scala -e "println(\"Hello\")" Hello</lang><lang cmd> PS C:\> scala -e 'println(\"Hello\")' Hello</lang> The escaping of quotes is required by Windows. On Unix and shown in the example on Windows PowerShell, one could just use single quotes around the code.


Works with: Guile

<lang scheme>guile -c '(display "Hello, world!\n")'</lang>


<lang shiny>shiny -e "say 'hi'" </lang>


<lang slate>./slate --eval "[inform: 'hello'] ensure: [exit: 0].".</lang>


Portable version <lang snobol>echo 'a output = "Hello, World!";end' | snobol4 -b</lang>

Bash version <lang snobol>snobol4 -b <<<'a output = "Hello, World!";end'</lang>


This is an area where Tcl is lacking, though when shell one-liners are required a construct like this is typically used: <lang bash>$ echo 'puts Hello' | tclsh Hello</lang>


<lang bash>$ echo 123-456-7890 | txr -c '@a-@b-@c' - a="123" b="456" c="7890" </lang>

Most useful txr queries consist of multiple lines, and the line structure is important. Multi-liners can be passed via -c easily, but there is no provision in the syntax that would allow multi-liners to be actually written as one physical line. There are opposite provisions for splitting long logical lines into multiple physical lines.

The -e (evaluate) and -p (evaluate and print) options provide shell one-liner access to TXR Lisp:

<lang bash>$ txr -p '(+ 2 2)' 4</lang>

<lang bash>$ txr -e '(mkdir "foo" #o777)' $ ls -ld foo drwxrwxr-x 2 kaz kaz 4096 Mar 4 23:36 foo</lang>

UNIX Shell

Explicit call of the shell, passing the shell command via the -c option: <lang bash>$ sh -c ls</lang> <lang bash>$ sh -c "echo hello"</lang>

To invoke a specific shell like Bash, Korn Shell or Z Shell:

<lang bash>$ bash -c 'paste <(echo 1) <(echo 2)' $ ksh -c 'let i=3+4; print $i' $ zsh -c 'if 5 -lt 6 { echo ok };'</lang>

Shell scripts almost never use sh -c, because there are various implicit ways whereby the shell command language evaluates a command in a subshell:

<lang bash>$ VAR=`echo hello` # obsolescent backtick notation $ VAR=$(echo hello) # modern POSIX notation $ (echo hello) # execute in another shell process, not in this one</lang>

There are more details about `echo hello` and $(echo hello) at Execute a system command#UNIX Shell.

C Shell

Run a C shell command from any shell:

<lang bash>$ csh -fc 'if (5 < 6) echo ok'</lang>


Run a command, in extensible shell, from any shell:

<lang bash>$ es -c 'if {test 5 -lt 6} {echo ok}'</lang>


The command to execute the Ursala compiler is fun. An expression supplied as a parameter to the --main option is compiled and evaluated. If the expression evaluates to a list of character strings, it can be displayed on standard output with --show. If it's some other type, it can be formatted for display by --cast <type expression>,

<lang bash>$ fun --main=-[hello]- --show hello $ fun --main="power/2 32" --cast %n 4294967296 $ fun --m="..mp2str mpfr..pi 120" --c %s '3.1415926535897932384626433832795028847E+00'</lang>

Vedit macro language

The following DOS command starts Vedit and displays a message. When the user presses any key, Vedit exits. <lang cmd>vpw -c'Get_Key("Hello!") exit'</lang>


<lang bash>echo "prn 34" |wart</lang>