I am just guessing like Corion

m{
\Qabc\E
| \Qabc-def\E
| \Qabc_def.12\E
| \Q.abc\E
| \Q.abc_123\E
| \Q.abcd-def\E
| \Qabcd.123.def\E
}x;
[download]

Read perlintro#More complex regular expressions or perlrequick#Matching this or that

See also Regexp::Assemble/Regexp::Trie/Regex::PreSuf/Regexp::Wildcards

P.S. At some point "guessing" stops being fun and help does not follow; I know what I mean. Why don't you? , How to ask questions the smart way.