[ILUG] grep, egrep, fgrep

[Padraig Brady]

Hmm this is interesting.

pixelbeat at pixelbeat:~$ ls -li /bin/ls /bin/dir /bin/vdir
1120272 -rwxr-xr-x    1 root     root       40848 Jan  5 14:10 /bin/dir
1120274 -rwxr-xr-x    1 root     root       40848 Jan  5 14:10 /bin/ls
1120280 -rwxr-xr-x    1 root     root       40848 Jan  5 14:10 /bin/vdir

I don't agree that they should be different files.
Why would you ever want to rename dir/ls/vdir/grep/fgrep/egrep/... ?
maybe if you had links with a different name but why?
What would be more appropriate in my opinion would be to return
an error if argv[0] wasn't one of the accepted values.

Padraig.

Scanlan, Brian (5188) wrote:

> Hey,
> 
> This is on RH 6.1 and 6.2...
> 
> # ls -ali /bin/grep /bin/egrep /bin/fgrep
>   16537 -rwxr-xr-x   1 root     root        47452 Mar 21  1999 /bin/egrep
>   16538 -rwxr-xr-x   1 root     root        47452 Mar 21  1999 /bin/fgrep
>   16539 -rwxr-xr-x   1 root     root        47452 Mar 21  1999 /bin/grep
> 
> Oooh, same sized file. Diff reckons they're different though.
> 
> # diff /bin/egrep /bin/grep
> Binary files /bin/egrep and /bin/grep differ
> 
> Hmm. Let's get a strings output...
> 
> # strings /bin/egrep >/tmp/egrep.strings
> # strings /bin/fgrep >/tmp/fgrep.strings
> # diff /tmp/egrep.strings /tmp/fgrep.strings
> 272c272
> < egrep
> ---
> 
>> fgrep
> 
> Is it just me, or are these three binarys the exact same apart 
> from a string containing their name, it'd be silly if they don't 
> act as their argv[0] says they should. 
> 
> Though this guy disagrees. 
> http://mail.gnu.org/pipermail/bug-gnu-utils/2000-January/000616.html
> 
> Brian.
> 
> -----Original Message-----
> From: Niall O Broin [mailto:niall at magicgoeshere.com]
> Sent: 02 February 2001 14:04
> To: ilug at linux.ie
> Subject: [ILUG] grep, egrep, fgrep
> 
> Can anyone shed any light on why the above, at least on SuSE 6.4, are
> entirely separate programs ? As egrep is e.g functionally identical to grep
> -E and the man page for grep says
> 
> In addition, two variant programs egrep and fgrep are available.  Egrep is
> the same as grep -E.  Fgrep is the same as grep -F.
> 
> why are grep, egrep, and fgrep not just links to the same file, and the
> program decides what to do according to its name as is quie common behaviour
> with Gnu tools ?
> 
> 
> This anomalous behaviour has just cost me a couple of blank CDs and more
> important, a couple of hours, so I'm pissed ! (Yes, I know it's my fault for
> making unjustified assumptions, but I'm still pissed !)