Not positive I've understood your question correctly, but are you looking for something like this?

#!/usr/bin/perl
use 5.016;
use warnings;

# 1069225  save match templates for reuse?

my $regex = qr/(sdfsd|abc|def|hijk)/;
say "\t regex is: $regex\n";

my @string = ('xyzalmnopdef',
              'sdfsd',
              'hijk lmn op',
              'babcdefijk2345',
              'xaybz3',
             );

for my $string(@string) {
    if ( $string =~ /($regex)/g ) {  # /g only if you expect to 
                                     # find more than one match per li
+ne
        say "got a match in $string: $1";

    }else{
        say "\t No match found in $string";
    }
}
[download]

Execution:

C:\>1069225.pl
          regex is: (?^u:(sdfsd|abc|def|hijk))

got a match in xyzalmnopdef: def
got a match in sdfsd: sdfsd
got a match in hijk lmn op: hijk
got a match in babcdefijk2345: abc
         No match found in xaybz3

C:\>
[download]

At the worst, perhaps this offers some help.

Update/PS: Failed to explain the /g. Fixed with comment in code.