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Re: Uncommon but Useful Perl Command Line Options

by hardburn (Abbot)
on Jan 28, 2004 at 22:01 UTC ( #324810=note: print w/replies, xml ) Need Help??

in reply to Uncommon* but Useful Perl Command Line Options for One-liners

'-l' has a dual nature - on input it behaves like chomp(), automatically removing newline characters, while on output, as we've seen, it becomes the anti-chomp, adding newlines.
. . .
-0 . . . Using this is like messing with $/ in a script . . .

For completeness, I would mention that '-l' is implemented by messing with $\ and $/:

$ perl -MO=Deparse -le '' -e syntax OK BEGIN { $/ = "\n"; $\ = "\n"; } ();

Also, you can specifiy a different character (in octal) on the command line for -l to use for $\ (output records):

$ perl -MO=Deparse -l001 -e '' -e syntax OK BEGIN { $/ = "\n"; $\ = "\001"; } ();

-0 can also take an octal number, but this time it sets $/ (input records):

$ perl -MO=Deparse -0001 -e '' -e syntax OK BEGIN { $/ = "\001"; $\ = undef; } ();

I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

: () { :|:& };:

Note: All code is untested, unless otherwise stated

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