Hello monks. I am a n00b and I am trying to fix some scripts that i didnt write and I am stumped on a regular expression
If you have time you might want to peruse the documentation on regexes in general at perlreftut and perlre).
As you might run into more regular expressions you might want to look into using YAPE::Regex::Explain which makes deciphering Regexes easy for instance
perl -MYAPE::Regex::Explain -e 'print YAPE::Regex::Explain->new(qr/^(\
+s^+)MVA/o)->explain;'
will return the following for your first regex:
The regular expression:
(?-imsx:^(\s^+)MVA)
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
----------------------------------------------------------------------
( group and capture to \1:
----------------------------------------------------------------------
\s whitespace (\n, \r, \t, \f, and " ")
----------------------------------------------------------------------
^+ the beginning of the string (1 or more
times (matching the most amount
possible))
----------------------------------------------------------------------
) end of \1
----------------------------------------------------------------------
MVA 'MVA'
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------
and then for the second one:
perl -MYape::Regex::Explain -e 'print YAPE::Regex::Explain->new(qr/(\s
++)/o)->explain;'
The regular expression:
(?-imsx:(\s+))
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):
----------------------------------------------------------------------
( group and capture to \1:
----------------------------------------------------------------------
\s+ whitespace (\n, \r, \t, \f, and " ") (1
or more times (matching the most amount
possible))
----------------------------------------------------------------------
) end of \1
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------
HTH
-enlil
