[H-GEN] regular expressions

[Michael Anthon]

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> > If you want to handle tabs and such as well, try this...
> > sed "s/[[:space:]]\+/|/g"
> 
> I always trap my sed expressions in forward-quotes to hide them
> completely from the shell.  [ObPeeve:  forward quotes cannot be
> escaped from bash _at all_.]
> 
I'm reading between the lines here a bit, so if I am misinterpreting,
then I apologise.... the \ before the + is NOT there for any shell
expansion reasons.  The double quote are there to prevent the shell from
changing \+ to just +, here's an extract from the 'ed' man pages...

       \+      Matches the single character regular expression or
               subexpression immediately preceding it one or more
               times.   So  the regular expression `a+' is short­
               hand for `aa*'.  If \+ occurs at the beginning  of
               a  regular  expression  or  subexpression, then it
               matches a literal `+'.

Cheers
Michael Anthon

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