According to the manual page of grep-Programs,
In addition, two variant programs egrep and fgrep are available. egrep is the same as ‘grep -E’. fgrep is the same as ‘grep -F’.
Direct invocation as either egrep or fgrep is deprecated, but is provided to allow historical applications that rely on them to run unmodified.
Why are they deprecated?
Best Answer
They have been removed from POSIX, with the following rationale:
So
egrep
andfgrep
are basically temporary artifacts on the way to a completegrep
, which has now been available for a long time; they have served their purpose and are no longer needed, hence their deprecation.Further evidence for this is to be found in old Unix releases:
egrep
andfgrep
didn’t have separate manpages, they were documented in thegrep
manpage, which states explicitly