bangor has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks, I am trying to write a regex that will capture a mail id from a sendmail log file line. When there are a big number of multiple recipients their ids are listed over multiple lines and a number is added to the id: 

# normal line
w7R9Kstc017510: split:

# split lines
w7R9Kstc017510[1]: split:
w7R9Kstc017510[2]: split:

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The regex needs to capture both variations - this is what I tried: 

/(\w+)(?:\[\d+\]): split:/

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But that doesn't capture the normal line.

Replies are listed 'Best First'.
Re: Help with regex
by 1nickt (Canon) on Sep 04, 2018 at 23:01 UTC

    Hi, you need to make the optional part optional: 

    perl -Mstrict -wlE '
my @str=("w7R9Kstc017510: split:","w7R9Kstc017510[1]: split:","w7R9Kst
+c017510[2]: split:");
for (@str) {
say "$_ matches" if /(\w+)(?:\[\d+\])?: split:/ 
#                               here ^
}
'
w7R9Kstc017510: split: matches
w7R9Kstc017510[1]: split: matches
w7R9Kstc017510[2]: split: matches

    [download]
    Hope this helps!


    The way forward always starts with a minimal test.
[reply]
[d/l]
      Thanks 1nickt, that works perfectly.
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