Solved

what does this perl regex do

Posted on 2011-03-17
3
292 Views
Last Modified: 2013-11-05
$ScriptName     = $0;
$ScriptName     =~ s!^.*/!!;

I am trying to understand what does  this regex in a perl script do

thanks

0
Comment
Question by:alienXeno
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
3 Comments
 
LVL 84

Expert Comment

by:ozo
ID: 35154608
perl -mYAPE::Regex::Explain -e 'print YAPE::Regex::Explain->new(qr!^.*/!)->explain'
The regular expression:

(?-imsx:^.*/)

matches as follows:
 
NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  ^                        the beginning of the string
----------------------------------------------------------------------
  .*                       any character except \n (0 or more times
                           (matching the most amount possible))
----------------------------------------------------------------------
  /                        '/'
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------


perldoc perlop
...
       s/PATTERN/REPLACEMENT/msixpogce
               Searches a string for a pattern, and if found, replaces that
               pattern with the replacement text and returns the number of
               substitutions made.  Otherwise it returns false (specifically,
               the empty string).



perldoc perlvar
...
       $PROGRAM_NAME
       $0      Contains the name of the program being executed.

0
 
LVL 75

Accepted Solution

by:
käµfm³d   👽 earned 250 total points
ID: 35156273
__NO POINTS__

The net effect of this regex is that everything from the start of the string up to and including the last occurrence of a forward slash will be replaced by an empty string. The exclamation points are pattern delimiters.
0
 
LVL 6

Author Comment

by:alienXeno
ID: 35156359
thank you very much
0

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Whatever be the reason, if you are working on web development side,  you will need day-today validation codes like email validation, date validation , IP address validation, phone validation on any of the edit page or say at the time of registration…
As most anyone who uses or has come across them can attest to, regular expressions (regex) are a complicated bit of magic. Packed so succinctly within their cryptic syntax lies a great deal of power. It's not the "take over the world" kind of power,…
Learn how to match and substitute tagged data using PHP regular expressions. Demonstrated on Windows 7, but also applies to other operating systems. Demonstrated technique applies to PHP (all versions) and Firefox, but very similar techniques will w…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…

626 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question