finding a friggin tab with sed or grep

[morphman]

Ok. Ive posted on about every linux forum i could find so far and no one seems to know the answer to this one: how in the blazes do you find a "tab" when using grep or sed? Here are some things ive already tried:
grep '\t' filename
grep '[:space:]' filename
grep '[:tab:]' filename
grep '<tab>' filename
grep '(actually hitting tab here)' filename
Ive also tried some slightly more cryptic things like creating a file with only a tab (we'll call the file "tab" here) and trying something like this:
fgrep -f tab filename
and sure enough that works for finding only a tab but i need to find a tab like in the middle of a regular expression and its driving me nuts! Yes, im aware that there are ways to get around specific instances of this by using a pipeline with awk (which does accept \t as a tab, btw) but i really need some way to reference *an actual tab when using sed or grep. My next option is to try using the ASCII code for a tab and see if that works. Does anyone know how to do that either? Thanks, and ill be 100% impressed if you know the answers to the questions. Thanks!!!!!

--Morphman
PS: i should also mention that im running Redhat 7.2.

[pam]

I do not have access to a Linux box right now, but would the following work?

egrep \t filename

I know it works on AIX, but then it works with ordinary grep too.

Also for GNU sed, I think you can enter a real tab if you precede it with a backslash. Again I can't test it so I might be lying

[morphman]

Nope, it doesnt work. Thanks though.

[pam]

Here I am writing from the comfort of my own Linux box, all I can say is I'm stumped. Sorry :-[

[pam]

Ok, I don't like to give up. This is one method....

tb=`printf "\t"`
grep "$tb" myfile

As you can see, it works by loading a shell variable with the tab character and using that as the search pattern.

Pam, you keep on impressing me..

[morphman]

Hmm, looks like it has potential ! im leaving work now so ill try it first thing tomorrow morning! Thanks! If it works in the middle of a regular expression ill be totally satisfied and you can take satisfaction in knowing that out of all of the forums ive posted on and all the linux people ive talked to, you would be the ONLY one who figured it out! For now, im going home, :P

[Feztaa]

Does it actually have to be a tab specifically?

If so, you should try ^I (type CTRL-V and then CTRL-I). That ought to work, but untested.

If you want to match spaces or tabs, use \s, which will match any whitespace as far as I know.

HTH.

[Feztaa]

Actually, I just tested the ^I thing and it works. You're welcome

[morphman]

Well, Pam i tried your technique but it doesnt seem to be working. I see what you are doing but wouldnt typing:
tb='printf "\t"'
just load *<printf \t> into the variable tb and then typing:
grep "$tb" filename *would in turn just say:
grep "printf \t" filename ?
im most likely doing something wrong if you got it to work. I tried doing exactly that and it didnt quite work. Im still a newbie so i need someone else to hold my hand and explain that one to me!
Feztaa!! That worked PERFECTLY! That was exactly what i was looking for, some non-cryptic normal way to insert a tab into a normal expression. Thanks folks, you are awesome. I was beginning to believe id never have any closure to this problem. Ill be sticking with linuxjunior in the future! * WOOHOO!!

--Morphman, exceptionally content linux newbie

PS: you have no idea how helpful this is!!

PS2: How did you find that Feztaa? Im always looking for more access to help tables and websites..