man : zforce(1)
ZFORCE(1) OpenBSD Reference Manual ZFORCE(1)
zforce - force gzip files to have a .gz suffix
zforce file ...
The zforce utility renames gzip(1) files to have a `.gz' suffix, so that
gzip(1) will not compress them twice. This can be useful if file names
were truncated during a file transfer. Files that have an existing
`.gz', `-gz', `_gz', `.tgz' or `.taz' suffix, or that have not been
compressed by gzip(1), are ignored.
zforce overwrites existing files without warning.
OpenBSD 4.9 May 31, 2007 OpenBSD 4.9