Re: recently introduced egrep problem

["Mark J. Reed" <markjreed at gmail dot com>]

On Oct 14 07:16, rick lavery wrote:
> Up until a recent release of grep I could execute this command in
> cygwin and it worked without any problems.
>
> echo 20081013193545 | egrep -Eo '[0-9]{1,2}'

As Corinna pointed out, the command "egrep -E" is redundant, since
"grep -E" is just GNUese for "egrep".  Use either "grep -Eo" or "egrep
-o" instead.  The same logic applies to "fgrep" and "grep -F".
(Arguably, "egrep" is more portable than "grep -E", since it works on
non-GNU versions - and despite the deprecation warnings, I imagine
"egrep" and "fgrep" are far too ingrained in far too many shell
scripts ever to be removed outright - but the "-o" option is pure GNU
anyway.)

> This same command still works on other distributions such as centos,
> rhel4, rhel5, fedora core 9, etc.

It just depends on the version of GNU grep.  In 2.5.1, egrep -E is
allowed; in 2.5.3, it's not. (I'm not sure about 2.5.2).  So, yes, it
works on RHEL5, which comes with 2.5.1, but not in, say, Ubuntu
8.04LTS, which comes with 2.5.3.

-- 
Mark J. Reed <markjreed@gmail.com>

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