course i taught last week provided courseware that distinguished
between grep's basic RE support and "extended" RE support, which
surprised me as, on my fedora 27 system, the man page for grep has the
"In addition, the variant programs egrep and fgrep are the same as
grep -E and grep -F, respectively. These variants are deprecated, but
are provided for backward compatibility."
also, further down:
"grep understands three different versions of regular expression
syntax: “basic” (BRE), “extended” (ERE) and “perl” (PCRE). In GNU
grep there is no difference in available functionality between basic
and extended syntaxes."
that *seems* pretty clear, but i just want to confirm that, in gnu
grep these days, the extended REs are now available automatically and
don't require options like they used to. thoughts?
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