what does this piece of code mean?

skyworld_chen has asked for the wisdom of the Perl Monks concerning the following question:

hi,

i see a piece of code like this:

#!/bin/sh
exec run perl -w -x -S $0 ${1+"$@"} # -*-perl-*-
#!perl -w
[download]

can anybody help me to understand this? thanks.

Comment on what does this piece of code mean? Download Code

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Re: what does this piece of code mean? by kennethk (Abbot) on Apr 22, 2013 at 14:43 UTC
Essentially, this code is a little misdirection to encapsulate a Perl script inside a shell script. When it gets to the exec line, the shell re-runs the script file with perl. -x tells perl to search the file for the first occurrence of a `#!` that also has the word `perl`, and so fast forwards past all the shell script. A read-through of -S would probably also be informative, and should contain some familiar-looking code. #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply] [d/l] [select]
Re^2: what does this piece of code mean? by skyworld_chen (Acolyte) on Apr 23, 2013 at 05:45 UTC
Hi all, thanks for all of your kind replies	[reply]
Re: what does this piece of code mean? by daxim (Curate) on Apr 22, 2013 at 14:41 UTC
http://stackoverflow.com/questions/2308874/explain-the-deviousness-of-the-perl-preamble http://stackoverflow.com/questions/9143726/what-means-not-running-under-some-shell-in-perl-scripts http://stackoverflow.com/questions/12326903/long-eval-string-at-the-beginnning-of-perl-script	[reply]
Re: what does this piece of code mean? by Anonymous Monk on Apr 22, 2013 at 14:21 UTC
Did you try searching for it? `[-x -S $0 ${1+"$@"}] [ddg://site:perlmonks.org "-x -S $0 ${1+"$@"}"]` -x -S $0 ${1+"$@"} site:perlmonks.org "-x -S $0 ${1+"$@"}" -> Perl wrapper, execute perl script frm shell script	[reply] [d/l]