Change: Replace egrep usage with grep -E

[jameschensmith]

Summary

Replaces deprecated usage of egrep with grep -E. Resolves the warning egrep: warning: egrep is obsolescent; using grep -E.

What happened to egrep and fgrep?

7th Edition Unix had commands egrep and fgrep that were the counterparts of the modern ‘grep -E’ and ‘grep -F’. Although breaking up grep into three programs was perhaps useful on the small computers of the 1970s, egrep and fgrep were deemed obsolescent by POSIX in 1992, removed from POSIX in 2001, deprecated by GNU Grep 2.5.3 in 2007, and changed to issue obsolescence warnings by GNU Grep 3.8 in 2022; eventually, they are planned to be removed entirely.

— Usage - GNU Grep (section "What happened to egrep and fgrep?")

[alphapapa]

Thanks. I'll plan to merge this when I work on this project again.