Re: Regex and writing lines in file

#!/usr/bin/perl
use strict; use warnings;

my $file;
my $match = "that";
my $extra = "Hello, I snook in here\nme too!";
{
   local $/;
   $file = <DATA>;
   $file =~ s/$match\n([^\n]*)\n([^\n]*)/$match\n$1\n$2\n$extra/;
}
print $file;

__DATA__
this
that
leave me
leave me
move me
and me
[download]

Output

this
that
leave me
leave me
Hello, I snook in here
me too!
move me
and me
[download]

Cheers,
R.

Pereant, qui ante nos nostra dixerunt!

Comment on Re: Regex and writing lines in file Select or Download Code

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Re^2: Regex and writing lines in file by amma (Novice) on May 01, 2013 at 09:59 UTC
I opened the file in string context and was able to find the pattern successfully. But I could not substitute the matched pattern with required pattern `$extra = "This is i will place after match\n.an this too"; open (my $fh, '+<', $file); $data = <$fh>; $data = s/(.entry)\n([^\n])\n/$1\n$extra/` [download] The $1 is found successfully. But could not do the substitution in the file.	[reply] [d/l]
Re^3: Regex and writing lines in file by Random_Walk (Prior) on May 01, 2013 at 11:38 UTC
You have now substituted within the `$data` variable. Next you need to write the contents of `$data` back to the file. Try adding something like this after the substitution `# untested seek $fh, 0, 0; # rewind to the start of the file print $fh $data; # Write the entire file close $fh;` [download] Of course this may not be very efficient if you have a large file to alter, but then inserting into the middle of a very big file never is. If you are frequently updating random records in a file you may need to start thinking about using a database. Cheers, R. Pereant, qui ante nos nostra dixerunt!	[reply] [d/l] [select]
Re^4: Regex and writing lines in file by amma (Novice) on May 01, 2013 at 17:55 UTC
Partially worked for me. Thank you!	[reply]