info chown
é claro:
Some older scripts may still use '.' in place of the ':' separator.
POSIX 1003.1-2001 (*note Standards conformance::) does not require
support for that, but for backward compatibility GNU 'chown' supports
'.' so long as no ambiguity results. New scripts should avoid the use
of '.' because it is not portable, and because it has undesirable
results if the entire OWNER'.'GROUP happens to identify a user whose
name contains '.'.
No caso dos programas GNU
, vale a pena verificar não apenas man
, mas também info
páginas, porque o pessoal do GNU detesta páginas manpages (de man tar
).