use strict;
use Tie::File;

# some variables get set up here since we're using strict (wink)

tie @lines, 'Tie::File', 'GWSvc.log', memory=>$some_small_number;

for ($i=0; $i<$#lines; $i++) {
    if (/c9391b56-b174-441b-921c-7d63/) {
        for ($j=$i-5; $j <= $i+5; $j++) {
            print $lines[$j];
        }
    }
}