Multiline shebang

Multiline shebang is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Simple shebangs can help with scripting, e.g. #!/usr/bin/env python at the top of a Python script will allow it to be run in a terminal as "./script.py".

Occasionally, a more complex shebang line is needed. For example, some languages do not include the program name in ARGV; a multiline shebang can reorder the arguments so that the program name is included in ARGV.

The syntax for a multiline shebang is complicated. The shebang lines must be simultaneously commented away from the main language and revealed to Bash so that they can be executed.

Clojure

The namespace = basename = filename minus the extension must be passed as a value to Clojure's -m flag.

<lang clojure>":";exec clj -m `basename $0 .clj` $0 ${1+"$@"} ":";exit</lang>

Common Lisp

Here, the script name is passed once to CLISP and once to ext:*args*, which normally omits it.

<lang lisp>#!/bin/bash

1. |

exec clisp -q -q $0 $0 ${1+"$@"} exit |#</lang>

Emacs Lisp

<lang lisp>:;exec emacs -batch -l $0 -f main $*</lang>

Erlang

This example is incorrect. Please fix the code and remove this message. Details: This is not a multiline shebang. A plain #! can only have one line.

Note that the binary is escript, not erl. The latter refuses to compile or run code that contains a shebang.

<lang erlang>#!/usr/bin/env escript</lang>

Haskell

This example is incorrect. Please fix the code and remove this message. Details: This is not a multiline shebang. A plain #! can only have one line.

A plain shebang will do.

<lang haskell>#!/usr/bin/env runhaskell</lang>

JavaScript

Works with: Node.js

This example is incorrect. Please fix the code and remove this message. Details: This is not a multiline shebang. A plain #! can only have one line.

A plain shebang will do.

<lang javascript>#!/usr/bin/env node</lang>

Lua

This example is incorrect. Please fix the code and remove this message. Details: This is not a multiline shebang. A plain #! can only have one line.

A plain shebang will do.

<lang lua>#!/usr/bin/env lua</lang>

newLISP

This example is incorrect. Please fix the code and remove this message. Details: This is not a multiline shebang. A plain #! can only have one line.

A plain shebang will do.

<lang lisp>#!/usr/bin/env newlisp</lang>

Perl

From perldoc perlrun, the following is supposed to find perl one way or another under sh, csh or perl. <lang perl>#!/usr/bin/perl eval '(exit $?0)' && eval 'exec perl -wS $0 ${1+"$@"}' & eval 'exec /usr/bin/perl -wS $0 $argv:q' if $running_under_some_shell;</lang>

Python

This example is incorrect. Please fix the code and remove this message. Details: This is not a multiline shebang. A plain #! can only have one line.

A plain shebang will do.

<lang python>#!/usr/bin/env python</lang>

R

This example is incorrect. Please fix the code and remove this message. Details: This is not a multiline shebang. A plain #! can only have one line.

Note that the binary is Rscript, not the R interpreter. Regardless, scripts must end with q("no") in order to terminate and return to the shell.

<lang R>#!/usr/bin/env Rscript</lang>

Ruby

This example is incorrect. Please fix the code and remove this message. Details: This is not a multiline shebang. A plain #! can only have one line.

A plain shebang will do.

<lang ruby>#!/usr/bin/env ruby</lang>

Scheme

Works with: Chicken Scheme

#| ... |# provides just the right environment for the multiline shebang. Here, the script name is passed once to the Chicken Scheme Interpreter and once to be picked up in args.

<lang scheme>#!/bin/bash

1. |

exec csi -ss $0 ${1+"$@"} exit |#</lang>

Smalltalk

<lang smalltalk>"exec" "gst" "-f" "$0" "$0" "$@" "exit"</lang>

Tcl

It is normal to use a line like this: <lang tcl>#!/usr/bin/env tclsh</lang> But in cases where that is not enough — perhaps because it needs some logic to locate the Tcl interpreter to use — the differences in the way Tcl and the Bourne shell interpret end-of-line backslashes in comments can be used: <lang tcl>#!/bin/sh

1. Next line is comment in Tcl, but not in sh... \

exec tclsh "$0" ${1+"$@"}</lang> Additional complexity can be added so long as the lines for the shell are commented in a Tcl sense.