Re^2: Issue with #!usr/bin/perl

[tobyink]

Actually on Windows, the shebang line is not ignored. The Operating System ignores it, but Perl pays attention. Compare:

#!/usr/bin/perl
print undef;

with:

#!/usr/bin/perl -w
print undef;

The former issues no warning; the latter warns about using an uninitialized value.

This is because in Perl, the shebang line performs two roles. It's used by Unix-like operating systems as a "dispatch mechanism" - to decide which program should interpret the script. And on all operating systems Perl parses it looking for command-line options. It doesn't honour all command line options found there (e.g. -M) but does some (like -w and -t).

[DrHyde]

There's also this useful trick for writing perl scripts that will run using whatever is the first perl in the $PATH:

#!/bin/sh

exec perl -x $0

#!perl
# your perl code goes here

"But why not use #!/usr/bin/env perl?", I hear you cry.

Because env isn't always in /usr/bin - it's in /bin on some obscure platforms - and there can be "issues" with passing arguments to the executable via env.

[nagalenoj]

Thanks for the clarification. As I haven't used windows machine for perl scripting, never encounter such and I didn't know this before.

Thanks.

[Anonymous Monk]

what's the difference between shebang -w vs. use strict; use warnings; ? Thinking of putting a shebang at the top of all my scripts that say #!/perl/shebang - be a win32 japh you know this is pointless, even with the -w.

[Anonymous Monk]

what's the difference between shebang -w vs. use strict; use warnings; ?

"use warnings" is lexical and -w is global. What's wrong with * w* and $^W