Shell one-liner: Difference between revisions

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Revision as of 14:51, 6 February 2010

Task
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.

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.

ALGOL 68

Works with: ALGOL 68G version Any - tested with release mk15-0.8b.fc9.i386 - Interpret straight off
$ a68g -e 'print(("Hello",new line))'

Output:

Hello
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:

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

Output:

Hello

AutoHotkey

<lang autohotkey>RunWait, %comspec% /c systeminfo > tmp,,Hide FileRead, var, tmp FileDelete, tmp MsgBox,% var</lang>

AWK

Maybe the most common way one can use awk is from the command line for one-liners, feeding the interpreter with an input.

$ awk 'BEGIN { print "Hello"; }'

A more "complex" and "real" example:

$ awk '/IN/ { print $2, $4; }' <input.txt

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

C

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...

$ echo 'main() {printf("Hello\n");}' | gcc -w -x c -; ./a.out

Clojure

clj-env-dir comes with clojure-contrib.

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

  1. 'user/add2

42 </lang>

Common Lisp

Varies by implementation

Works with: SBCL

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

Works with: CLISP

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

E

Some lines in this example are too long (more than 80 characters). Please fix the code if it's possible and remove this message.

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

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

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

Emacs Lisp

<lang sh>emacs -batch -eval '(princ "Hello World!\n")' </lang>

Or another example that does something useful: indent a C source file:

<lang sh>emacs -batch sample.c --eval '(indent-region (point-min) (point-max) nil)' -f save-buffer</lang>

Erlang

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).

$ erl -noshell -eval 'io:format("hello~n").' -s erlang halt
hello

Factor

$ factor -run=none -e="USE: io \"hi\" print"

Forth

Works with: GNU Forth
$ gforth -e ".( Hello) cr bye"
Hello

F#

> echo printfn "Hello from F#" | fsi --quiet
Hello from F#

Haskell

$ ghc -e 'putStrLn "Hello"'
Hello

J

$ jconsole -js "exit echo 'Hello'"
Hello

JavaScript

Works with: SpiderMonkey
$ js -e 'print("hello")'
hello

OCaml

$ ocaml <(echo 'print_endline "Hello"')
Hello

Perl

$ perl -e 'print "Hello\n"'
Hello

Perl 6

Works with: Rakudo version #22 "Thousand Oaks"
$ perl6 -e 'say "Hello, world!"'
Hello, world!

PHP

assuming you have the PHP CLI (command-line interface) installed, not just the web server plugin

$ php -r 'echo "Hello\n";'
Hello

Pike

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

PowerShell

> powershell -Command "Write-Host 'Hello'"
Hello

Python

$ python -c 'print "Hello"'
Hello

R

$ echo 'cat("Hello\n")' | R --slave
Hello

Alternatively, using the Rscript front-end,

$ Rscript -e 'cat("Hello\n")'
Hello

REBOL

rebview -vswq --do "print {Hello!} quit" 

Output:

Hello!

Ruby

$ ruby -e 'puts "Hello"'
Hello

Scala

C:\>scala -e "println(\"Hello\")"
Hello

The escaping of quotes is required by Windows. On Unix, one could just use single quotes around the code. In either case, any required libraries should have their JAR files pointed at by the environment variable CLASSPATH.

Slate

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

Tcl

This is an area where Tcl is lacking, though when shell one-liners are required a construct like this is typically used:

$ echo 'puts Hello' | tclsh
Hello

(This apparent weakness is purposeful; it leaves a larger fraction of the space of possible arguments open to use by the script being executed.)

Ursala

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>,

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