grep replacement

[Geoff Clare]

Most of the useful things people have been saying they would like to be
able to do with 'grep' can already be done very simply with 'sed'.
For example:

    Stop after first match:   sed -n '/pattern/{p;q;}'

    Match over two lines:     sed -n 'N;/pat1\npat2/p;D'

It should also be possible to get a small number of context lines by
judicious use of the 'hold space' commands (g, G, h, H, x), but I haven't
tried it.  Anyway, this can be done with a normal line editor (if the data
to be searched aren't coming from a pipe) with 'g/pattern/-,+p'.

I was rather alarmed to see the proposal for 'pattern repeat' in the original
article was '\{pattern\}\1' rather than '\(pattern\)\1', as the latter is
already used for this purpose in the standard editors (ed, ex/vi, sed).
Or was it a typo?

By the way, does anyone know why the ';' command terminator in 'sed' is
not documented?  It works on all the systems I've tried it on, but I
have never found it in any manuals.  It's so much nicer than putting
the commands on separate lines, or using multiple '-e' options.
-- 

Geoff Clare    UniSoft Limited, Saunderson House, Hayne Street, London EC1A 9HH
gwc at root.co.uk   ...!mcvax!ukc!root44!gwc   +44-1-606-7799  FAX: +44-1-726-2750