Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic
 
PerlMonks  

Re^2: Using Look-ahead and Look-behind

by Corion (Patriarch)
on Nov 28, 2024 at 06:18 UTC ( [id://11162925]=note: print w/replies, xml ) Need Help??


in reply to Re: Using Look-ahead and Look-behind
in thread Using Look-ahead and Look-behind

You're reading your input line-by-line but you're trying to match across lines. That won't work.

The following should work, reading the input all at once (see perlrun):

perl -g -i -pe ’s/(?<=look)\n(?=ahead)/-/g;’ myfile.txt

Replies are listed 'Best First'.
Re^3: Using Look-ahead and Look-behind
by akiemr19 (Initiate) on Nov 28, 2024 at 13:24 UTC

    Thank you very, very much for setting me on the right path! While (in my environment) the -g switch isn't allowed for (what I learned to be was) slurping, instead using the -0777 switch did work nicely. I had seen this switch before, but until now wasn't aware of its usage until I dug deeper, prompted by your input.

    I was stuck on this for a long time - thanks again for the quick response!

    P.S. I just found where version 5.36 would allow the use of the -g switch, which is apparently a shortcut for using -0777.

      The -g only came in with perl 5.36 so won't be available in many LTS platforms unless they backport it. Using -0777 as you have mentioned is perfectly fine and, AFAIAA, will continue to be.


      🦛

Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Node Status?
node history
Node Type: note [id://11162925]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this?Last hourOther CB clients
Other Users?
Others examining the Monastery: (2)
As of 2025-07-12 03:46 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found

    Notices?
    erzuuliAnonymous Monks are no longer allowed to use Super Search, due to an excessive use of this resource by robots.