if (my (@captures) = $expr =~ /regex/) {
    # do something with @captures
} else {
    # did not match
}

if (my (@captures) = $expr =~ /(abc)ijk(def)lmn/) {
    # do something with @captures
    print "Daten $captures[0] sind vor $captures[1]";
} else {
    # did not match
}