| Date: Mon, 25 Mar 2002 17:05:39 +0000
| From: Padraig Brady <padraig at antefacto.com>
|[ ... ]
| sed -n -e "/[0-9]/p" testfile
| is the same as:
| grep "[0-9]" testfile
is a superset of both; ergo, by this logic,
_both_ grep and sed are superfluous.
superset because, e.g., ed can "go backwards"
in a file, whilst neither sed nor grep can.
hence, as an example, the previous challenge
of `grep -C5 re file' can be done as:
however, if you've ever tried to use ed in
a pipeline (e.g.), you'll probably quickly
appreciate why sed came to be.
as noted previously, both sed and grep were
originally derived from the more general ed.
so the argument seems to be they "shouldn't"
have been derived --- or even necessary? ---
in the first place. that seems to be an
unsupportable proposition, as it appears
to deny that specialist tools (e.g. hammers)
are needed when a general solution can be
used (e.g. rocks).
|[ ... ]
| I think it's as easy for someone to learn the p command
| in sed, as a seperate grep command. That just takes a
| minute or two. [ ... ]
whilst I question the example stated, there
is a similar example along those lines which
seems to have some validity:
head -20 file
is the same as:
sed 20q file
the "ease of typing" argument doesn't apply to
this example; and the "overhead" counter-argument
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