Here's a one-liner - I'm sure it could be golfed...

perl -ibak -a -ln00e "$,=qq/\n/;($t)=$F[1]=~'/([^/]*)$';$F[0]=~s/\[/[$t /;print @F,qq/\n/" filename

Here's another way - I moved your data into __DATA__ to simplify.

#!C:\Perl\bin\perl -w
use strict;

#paragraph mode - see perlvar, input record separator
$/ = "";
while(<DATA>)
{
  my @lines = split /\n/, $_;
  my $file;
  $lines[0] =~ s/\[/\[$file / if ($file) = $lines[1] =~ '/([^/]*)$';

        print join ("\n", @lines), "\n\n";
}

__DATA__
[get4]
$uri=/LRA/RiskApplicationPage.aspx
$method=GET

[get5]
$uri=/LRA/CSS/RiskManagement.css

$method=GET

[download]

The key is to change the input record separator, so each time you read you get a single complete record to manipulate.

Update: added "'" (single quote) in re line 10

In reply to Re: Need RegEx assistance by jsprat
in thread Need RegEx assistance by Anonymous Monk

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