Re: sed: backreference in substitution does not work as expected

From: Chris Mattern (syscjm_at_gwu.edu)
Date: 12/29/03 

Date: Mon, 29 Dec 2003 13:44:59 -0500

Ronald Fischer wrote:
> Could some friendly soul tell me why
>
> ... | sed -e 's/a(.)b/\1/'
>
> causes the error message
>
> sed: Function s/a(.)b/\1/ cannot be parsed
>
Because you have no referent for "\1". In sed
REs, if you wish parentheses to be metacharacters,
you must escape them with backslashes. This will
work:

sed -e 's/a\(.\)b/\1/'

         Chris Mattern

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