how to deal with newline

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

I want to match 2 strings on different lines in a file. The strings are not on the same line. New lines are coded as a <cr><lf> pair (windows).

My text file is myfile.txt:

..some random text..name="Bob"..some more random text containing new lines..
..some random text..id="437"..yet some more text

I tried the following which didn't work:

perl -ne "print \"$1\n$2\n\" while /name=\"(.*)\".*id=\"(.*)\"/gs" myfile.txt

What is wrong with this?

Comment on how to deal with newline Download Code

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Re: how to deal with newline by Corion (Patriarch) on Oct 27, 2013 at 15:27 UTC
`-n` reads the file line by line. Have you looked at what `$_` contains for each of your checks?	[reply] [d/l] [select]
Re: how to deal with newline by NetWallah (Canon) on Oct 27, 2013 at 16:38 UTC
Try this .. `perl -ne '$h{$1}=$2 for /(\w+)="([^"]*)"/g}{print qq($_\t= $h{$_}\n) f +or qw(id name)' myfile.txt id = 437 name = Bob` [download] Internal Quotes will have to be escaped and external quotes changed to be double-quotes for Windows. But you already knew that.... When in doubt, mumble; when in trouble, delegate; when in charge, ponder. -- James H. Boren	[reply] [d/l]
Re: how to deal with newline by Laurent_R (Canon) on Oct 27, 2013 at 16:55 UTC
Besides the line by line issue already identified, one of the problems with your regex is greedy match. If your line contains something like this: `'some random text..name="Bob"..some more random text surname="Dylan" some more text'` the `name=\"(.)\"` part of your regex will match as much as it can between quotes, i.e.: `Bob"..some more random text surname="Dylan` You have to either make your quantifier non greedy by adding the ? qualifier, `name=\"(.+?)\"`, or match characters which are anything but quotes, `name=\"([^"]+)\"` (I also changed * to + because it does not seem to make too much sense to match an empty string between quotes).	[reply] [d/l] [select]
Re: how to deal with newline by Lennotoecom (Pilgrim) on Oct 27, 2013 at 20:02 UTC
~~`perl -ne 'print $1,"\n" foreach /[name\|id]="(\w+)/' myfile.txt`~~ update on the second thought: `perl -ne 'print "$1\n" if /[name\|id]="(\w+)/' myfile.txt` [download] would be enough	[reply] [d/l] [select]