Here's a little script that might illustrate some of concepts presented by the other monks:

use strict;
my @data = <DATA>;

print "1:\n";
#1: print lines that contain something like '[[106535 abc]]'
foreach my $line (@data) {
  print $line if $line =~ /\[\[\d+ \w+\]\]/;
}

print '-' x 20, "\n2:\n";

#2: print lines that start with something like '[[106535 abc]]', but
#with an indeterminate number of brackets
foreach my $line (@data) {
  print $line if $line =~ /^\[+\d+ \w+\]+/;
}

print '-' x 20, "\n3:\n";

#3: print lines that start with something like '[[106535 abc]]'
foreach my $line (@data) {
  print $line if $line =~ /^\[\[\d+ \w+\]\]/;
}

print '-' x 20, "\n4:\n";

#4: print lines that start with two brackets, six digits,
#a space, three alphanumerics and two brackes
foreach my $line (@data) {
  print $line if $line =~ /^\[\[\d{6} \w{3}\]\]/;
}

print '-' x 20, "\n5:\n";

#5: print out the value inside of the brackets and then
#the rest of the line
foreach my $line (@data) {
  print "$1 - $2\n" if $line =~ /^\[\[(\d+ \w+)\]\]\s(.+)/;
}


__DATA__
[[106535 abc]] blah blah blah...
[[298727 xyz etc etc etc etc etc
[[093 hij]] so on and so on and so on
[[459313 def] more more more more
459313 yadda  yadda yadda yadda yadda
[[349581 wxy]] yack yack yack yack yack
they're coming to [[549412 qqq]] me away
ipsum plurum ipsum plurum ipsum plurum
... ... ... ...
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