grep -E instead of egrep?

grep -E instead of egrep?

[David Kastrup]

I saw the following change:

2006-10-15  Lennart Borgman  [...]

	* progmodes/ada-xref.el (ada-find-in-src-path): Likewise.
	Use grep -E rather than egrep.

Is there a particular reason to prefer "grep -E"?  I would have
thought that "egrep" is much more portable?

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum

Re: grep -E instead of egrep?

[Michaël Cadilhac]

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David Kastrup <dak@gnu.org> writes:

> I saw the following change:
>
> 2006-10-15  Lennart Borgman  [...]
>
> 	* progmodes/ada-xref.el (ada-find-in-src-path): Likewise.
> 	Use grep -E rather than egrep.
>
> Is there a particular reason to prefer "grep -E"?  I would have
> thought that "egrep" is much more portable?

The SUSv3  [1] doesn't have  any entry for  « egrep », and  only knows
about « grep -E ». egrep hasn't been « carried forward ».

So you're probably right about egrep being much more portable, because
it's been created before grep -E, but in the future, egrep is meant to
disappear.

Footnotes: 
[1]  http://www.unix.org/single_unix_specification/

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Re: grep -E instead of egrep?

[David Kastrup]

michael@cadilhac.name (Michaël Cadilhac) writes:

> David Kastrup <dak@gnu.org> writes:
>
>> I saw the following change:
>>
>> 2006-10-15  Lennart Borgman  [...]
>>
>> 	* progmodes/ada-xref.el (ada-find-in-src-path): Likewise.
>> 	Use grep -E rather than egrep.
>>
>> Is there a particular reason to prefer "grep -E"?  I would have
>> thought that "egrep" is much more portable?
>
> The SUSv3  [1] doesn't have  any entry for  « egrep », and  only knows
> about « grep -E ». egrep hasn't been « carried forward ».

Thanks, I did not know about that.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum

Re: grep -E instead of egrep?

[Richard Stallman]

    So you're probably right about egrep being much more portable, because
    it's been created before grep -E, but in the future, egrep is meant to
    disappear.

-E was specified by POSIX, more than a decade ago.
By now, we can assume it is supported.