Unix Help - Tail | Grep - GoFuckYourself.com

Dusen · 02-18-2004, 07:04 PM

I'm trying to grep a tail -f out to a file.

But it doesn't seem to be working.

I am doing:

tail -f file | grep 'term' > file.txt

No output to file.

Anyone see what is wrong? Any ideas how to do this?

Veiga · 02-18-2004, 07:09 PM

That's correct, and I just tried and it works with me.

Is the file created but empty?

Dusen · 02-18-2004, 07:12 PM

Yes, that is what is happening.

Dusen · 02-19-2004, 06:44 AM

Anyone else help? I'm stuck.

I've scripted something up in perl but when the file gets truncated the perl script stops outputting to file.

com · 02-19-2004, 06:49 AM

looks fine to me, post your code

Dusen · 02-19-2004, 07:17 AM

PHP Code:


			
#!/usr/bin/perl



while (1) {

open LOG, 'access_log' || die "no can open file: $!";



seek(LOG,0,2);

for(;;) {

headerloop: while(<LOG>)

{

        chomp;

        if (/.*(texttofilter).*/)

        {

        open YOURLOG, '>> /home/me/outputfile' || die "can not write to file";

        print YOURLOG "$_","\n";

        }



}

sleep(1);

seek(LOG,0,1);

close YOURLOG;

}

}

Thanks

The grep option works without sending to file AND sending to file works without the grep there. It seems that soemthing is messed up.

Dusen · 02-19-2004, 06:11 PM

Bump?

com · 02-19-2004, 06:16 PM

hrm, perhaps you might try using 2&>/path/to/file

edit I havent touched perl in ages but what you've got there looks fine to me.

com · 02-19-2004, 06:19 PM

im sure im probably mistaken but shouldn't

>> /home/me/outputfile

be

> /home/me/outputfile

or at least have a statement to use concatonate or append depending on weather or not the file exists. *shrug*

Dusen · 02-19-2004, 06:22 PM

Hrmm, well depending on what I want to do, >> is just because I don't want to kill what is there now. Appending is much better for me.

I don't even need to use that script, I just need to tail -f a logfile and grep the output to another file. That's it.

I'm lost.

Dusen · 02-20-2004, 07:59 AM

A Final Bump

Alky · 02-20-2004, 08:04 AM

hate to ask a stupid question, but is there anything in the file your trying to tail?

some_idiot · 02-20-2004, 08:30 AM

It's the way that grep dumps the data pipe into standard out.

Give who | sort >> user.txt a try and I bet it works for you.

You're going to need to write a quick hack in perl to open a file
and then dump all standard input to it. Stick that in place of
the >> yourfile in your pipe chain. tail | grep | hack.pl

...or spend all day pulling your hair out searching for an answer
you probably won't find.

extreme · 02-20-2004, 08:34 AM

output buffering .. need to reach a certain amount of lines before the last pipe gets it.

extreme · 02-20-2004, 08:54 AM

and ...

tail -f file | awk '/term/ { print; fflush() }' > file.txt

.. solves it.

Dusen · 02-20-2004, 10:04 AM

Quote:

Originally posted by extreme
and ...

tail -f file | awk '/term/ { print; fflush() }' > file.txt

.. solves it.

Outstanding, it sure does.

Thanks a BUNCH, I really appreciate it.

Thanks to everyone who helped in this thread, I knew there were some fellow nix dorks lurking around here and I wasn't alone.

J

02-18-2004, 07:04 PM	#1
Dusen Confirmed User Join Date: Aug 2002 Location: East Coast. Posts: 2,251	Unix Help - Tail \| Grep I'm trying to grep a tail -f out to a file. But it doesn't seem to be working. I am doing: tail -f file \| grep 'term' > file.txt No output to file. Anyone see what is wrong? Any ideas how to do this? __________________ Penis Pill Sponsor List and Reviews: http://www.pillsponsors.com

02-18-2004, 07:09 PM	#2
Veiga Confirmed User Join Date: Jun 2001 Location: Portugal Posts: 157	That's correct, and I just tried and it works with me. Is the file created but empty? __________________ Sell me your portuguese Traffic! Euro Luso

02-18-2004, 07:12 PM	#3
Dusen Confirmed User Join Date: Aug 2002 Location: East Coast. Posts: 2,251	Yes, that is what is happening. __________________ Penis Pill Sponsor List and Reviews: http://www.pillsponsors.com

02-19-2004, 06:44 AM	#4
Dusen Confirmed User Join Date: Aug 2002 Location: East Coast. Posts: 2,251	Anyone else help? I'm stuck. I've scripted something up in perl but when the file gets truncated the perl script stops outputting to file. __________________ Penis Pill Sponsor List and Reviews: http://www.pillsponsors.com

02-19-2004, 06:49 AM	#5
com Confirmed User Join Date: Aug 2003 Location: Portland, Oregon Posts: 4,541	looks fine to me, post your code __________________ Real. Professional. Hosting. .:Expect Nothing Less:. 320-078-843 :: www.realprohosting.com :: [email protected]

02-19-2004, 07:17 AM	#6
Dusen Confirmed User Join Date: Aug 2002 Location: East Coast. Posts: 2,251	PHP Code: `#!/usr/bin/perl while (1) { open LOG, 'access_log' \|\| die "no can open file: $!"; seek(LOG,0,2); for(;;) { headerloop: while(<LOG>) { chomp; if (/.(texttofilter)./) { open YOURLOG, '>> /home/me/outputfile' \|\| die "can not write to file"; print YOURLOG "$_","\n"; } } sleep(1); seek(LOG,0,1); close YOURLOG; } }` Thanks The grep option works without sending to file AND sending to file works without the grep there. It seems that soemthing is messed up. __________________ Penis Pill Sponsor List and Reviews: http://www.pillsponsors.com

02-19-2004, 06:11 PM	#7
Dusen Confirmed User Join Date: Aug 2002 Location: East Coast. Posts: 2,251	Bump? __________________ Penis Pill Sponsor List and Reviews: http://www.pillsponsors.com

02-19-2004, 06:16 PM	#8
com Confirmed User Join Date: Aug 2003 Location: Portland, Oregon Posts: 4,541	hrm, perhaps you might try using 2&>/path/to/file edit I havent touched perl in ages but what you've got there looks fine to me. __________________ Real. Professional. Hosting. .:Expect Nothing Less:. 320-078-843 :: www.realprohosting.com :: [email protected]

02-19-2004, 06:19 PM	#9
com Confirmed User Join Date: Aug 2003 Location: Portland, Oregon Posts: 4,541	im sure im probably mistaken but shouldn't >> /home/me/outputfile be > /home/me/outputfile or at least have a statement to use concatonate or append depending on weather or not the file exists. shrug __________________ Real. Professional. Hosting. .:Expect Nothing Less:. 320-078-843 :: www.realprohosting.com :: [email protected]

02-19-2004, 06:22 PM	#10
Dusen Confirmed User Join Date: Aug 2002 Location: East Coast. Posts: 2,251	Hrmm, well depending on what I want to do, >> is just because I don't want to kill what is there now. Appending is much better for me. I don't even need to use that script, I just need to tail -f a logfile and grep the output to another file. That's it. I'm lost. __________________ Penis Pill Sponsor List and Reviews: http://www.pillsponsors.com

02-20-2004, 07:59 AM	#11
Dusen Confirmed User Join Date: Aug 2002 Location: East Coast. Posts: 2,251	A Final Bump __________________ Penis Pill Sponsor List and Reviews: http://www.pillsponsors.com

02-20-2004, 08:04 AM	#12
Alky Confirmed User Join Date: Apr 2002 Location: Houston Posts: 5,651	hate to ask a stupid question, but is there anything in the file your trying to tail?

02-20-2004, 08:30 AM	#13
some_idiot Confirmed User Join Date: May 2002 Location: Doesn't matter, I'm not buying you another pint! Posts: 1,511	It's the way that grep dumps the data pipe into standard out. Give who \| sort >> user.txt a try and I bet it works for you. You're going to need to write a quick hack in perl to open a file and then dump all standard input to it. Stick that in place of the >> yourfile in your pipe chain. tail \| grep \| hack.pl ...or spend all day pulling your hair out searching for an answer you probably won't find. __________________ This AVS pays my mortgage!

02-20-2004, 08:34 AM	#14
extreme Confirmed User Industry Role: Join Date: Oct 2002 Location: lalaland Posts: 2,120	output buffering .. need to reach a certain amount of lines before the last pipe gets it. __________________ Browse and find new paysites with screenshot-preview Export FHGs/FLVs/Paysites by JSON, XML, CSV and Text Find FHGs/FLVs/Paysites from any given Category or Search-query

02-20-2004, 08:54 AM	#15
extreme Confirmed User Industry Role: Join Date: Oct 2002 Location: lalaland Posts: 2,120	and ... tail -f file \| awk '/term/ { print; fflush() }' > file.txt .. solves it. __________________ Browse and find new paysites with screenshot-preview Export FHGs/FLVs/Paysites by JSON, XML, CSV and Text Find FHGs/FLVs/Paysites from any given Category or Search-query