Brief was first released in 1985. texteditors.org has useful info on Brief and clones and emulators of it. Wikipedia has similar lists. It is closed-source.
The changelog for version 4.50 states that it “Supports regular expression search and replace, both Brief and Perl syntax”. It wouldn't make sense to invent a regexp syntax at the same time as using Perl's, so I assume a version before 4.00 added Brief-syntax regexps and is not listed. Only Brief Professional has “Find and replace using regular expressions”.
Versions:
- Solutions Systems Brief 2.1
- Brief 3.1 disk image (may have sources)
- Brief 3.1 for DOS and OS2 manual
- Brief 3.1 for OS2
- Solutions Systems Brief 3.1
- Brief 3.11
- Brief Basic 4.00 (msi)
- Brief Basic 4.01 (msi)
- Brief Basic 4.02 (msi)
- Brief Basic 4.40 (msi)
- Brief Basic 4.50 (msi)