I am trying to understand the difference between
grep -e and
grep -E. Now from
grep manpage I got:
Interpret PATTERN as an extended regular expression (see below).
-e PATTERN, --regexp=PATTERN
Use PATTERN as the pattern; useful to protect patterns beginning with -
The above explanation does not make sense for me.
So, can someone explain it to me using
examples what is the difference between the two and when to use which option.
PS: Version: grep (GNU grep) 2.10
-eis really just to disambiguate when a regex starts with a dash. So
unrecognized option: ---foobut you can say
grep -e ---footo grep for the regular expression