Re: How to match regex in bash? (any character)

[Greg Wooledge]

On Mon, Sep 26, 2011 at 07:06:30PM -0800, Roger wrote:
> Some good reading I found is under the Bash Manual Page section "Parameter
> Expansion".
> 
> From here, to learn more about regex/regexpr as the Bash Manual is quite brief
> on regex, use the following manual pages:
> 
> perlretut - Gives a good from the start explanation of regular expressions,
> including perl

Perl's regular expressions are not the same as Bash's.  Bash uses standard
POSIX Extended Regular Expressions (ERE).  You can find formal documentation
at 
http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04

Or see "man egrep", as egrep (or grep -E) also uses EREs.  Or see any
web page that discusses EREs.

Avoid reading documentation from a different language (in this case Perl),
because the features tend to change.  Perl uses a feature set and syntax
that have been retroactively dubbed Perl Compatible Regular Expressions
(PCRE).  They're superficially similar to EREs, but have a much broader
range of features (extensions) that are not compatible and will not work
in Bash.