in reply to Match Ip Address on cmd line

This 'quick and dirty' regex will work reasonably well for "reasonable" data: 
    perl -ne 'print qq|$1\n| if m/^\s*((?:\d{1,3}\.){3}\d{1,3})\s*$/'

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It is tolerant of leading and trailing white-space, but does not check for octets being under 255, or being all zero at the first octet. There are "standard regex" Regexp::Common modules that do a more thorough check for IPv4 validity.

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Re^2: Match Ip Address on cmd line
by sans-clue (Beadle) on Sep 09, 2011 at 14:03 UTC
    thanks so much, does the trick. what does qq mean ?

    Also, yes I know this isn't a code writing service, but I could not find an 'if m/...' example in a command line, plus I would have never come up with 2 |'s

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      The things you ask about are partly about style choices.

      Equivalent: 

      do_something() if <condition>;
if (<condition>) { do_something(); }

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      Equivalent: 

      m[regex]
m|regex|
m/regex/
/regex/

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      Equivalent: 

      "string-with-expanded-$variables"
qq[string-with-expanded-$variables]
qq/string-with-expanded-$variables/

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      Using qq// is common on command lines, since the shell itself may require quotes or double-quotes.

      Equivalent: 

      'string-expanding-no-variables'
q[string-expanding-no-variables]
q/string-expanding-no-variables/

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      All of this can be found in perldoc perlsyn and perldoc perlop.

      --
      [ e d @ h a l l e y . c c ]

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        veddy nice I like. thanks
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