grepping the linux "time" command

[fiddlehead_cons]

Phellow Phreaks!
I'm trying to track the CPU usage of a short Linux script that I wrote called clientFeeder.do.  I want to grep out the system cpu time and log it into a file.  However, when I run the command:

time . clientFeeder.do >> grep sys 2>&1

I get all three times, real, user, and sys.

real    0m1.685s
user    0m0.033s
sys    0m0.027s

Can anyone tell me what I'm doing wrong?  ???  I just want the sys time, not the other two lines.  Thanks!

Warm regards,
James

[neylitalo]

well, you're close, but not quite - the syntax would actually be:

[code]$ time foobar 2>&1 | grep sys[/code]

It's odd, though - grep still doesn't seem to catch it, when I try it. Other stderr redirection works fine for me, but not with time. I suspect it's because time is a utility within bash, and that throws things off, for whatever reason.

[ypirc]

Alternatively, you could use the "time" bin and not the bash "builtin" command.  The benefit of this is that it has a  "format" flag that you can pass to _only_ return what you want.

[quote]
# /usr/bin/time -f "%S" ls >/dev/null
0.00
[/quote]

[neylitalo]

Oh, excellent. If you haven't got the GNU time utility, it's available at http://ftp.gnu.org/pub/gnu/time/time-1.7.tar.gz, in Gentoo's Portage as sys-process/time and in Debian's stable repos as utils/time.