http://www.perlmonks.org?node_id=417158


in reply to RegEx for users who dont know RegEx

One solution is to strip out all characters in the user-supplied data that aren't explicitly allowed and then generate your regex based off of that.

Update -- Try this sample code:

#!/usr/bin/perl use warnings; use strict; my $query = shift; die "usage: $0 query-string\n" if not $query; print "Original query: '$query'\n"; $query =~ s/[^\w\*]//g; print "Safe query: '$query'\n"; $query =~ s/\*/\\w\*/g; print "Parsed query: '$query'\n"; while (<DATA>) { print "match: $_" if /$query/i; } __DATA__ invitation information Isolation InFlaTiOn IATION In our nation it requires concentration at ionizing radiation
Note that "at ionizing radiation" matches because the iation in radiation matches. Did you just miss that, or should it not match?