Comment 10 for bug 67141

GREP_OPTIONS is useful, because it allows the user set one option for many forms of grep (grep, egrep, fgrep, rgrep, zgrep, bzgrep, bzfgrep, bzegrep, etc.).

For example, here's what the man page for bzgrep says:

    If the GREP environment variable is set, bzgrep uses it as the grep program to be invoked.

    For example:

           for sh: GREP=fgrep bzgrep string files
           for csh: (setenv GREP fgrep; bzgrep string files)

If you disable GREP_OPTIONS and insist that users replace it with an alias, then users will need to set an alias for every form of *grep, and there are many different greps.