Will McDonald wrote: > On 14/03/07, John Summerfield <debian at herakles.homelinux.org> wrote: >> Ryan Simpkins wrote: >> > >> > Am I using time right to measure it? >> No, you're timing the cat only. > > I don't think that's the case, you know. If I run the following: [summer at bilby ~]$ time sleep 10s;sleep 10s real 0m10.011s user 0m0.000s sys 0m0.003s [summer at bilby ~]$ time sleep 10s|sleep 10s real 0m10.002s user 0m0.001s sys 0m0.003s [summer at bilby ~]$ time sleep 10s | time sleep 10s 0.00user 0.00system 0:09.99elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+150minor)pagefaults 0swaps real 0m10.011s user 0m0.000s sys 0m0.006s [summer at bilby ~]$ > > [wmcdonald at stella ~]$ ls -lh /tmp/messages.1 > -rw-r--r-- 1 root root 4.3M Mar 14 20:03 /tmp/messages.1 > [wmcdonald at stella ~]$ time cat /tmp/messages.1 1> /dev/null > > real 0m0.018s > user 0m0.001s > sys 0m0.017s > > [wmcdonald at stella ~]$ time cat /tmp/messages.1 | grep '*.foo' 1> /dev/null > > real 0m0.047s > user 0m0.021s > sys 0m0.026s > > Running both commands repeatedly shows similar time differences, I > think 'time''s timing the execution time of the whole command. I think that writing to a pipe is more expensive than writing to /dev/null. Needs buffering etc. Try time cat /tmp/messages.1 | grep \ | grep '*.foo' 1> /dev/null -- Cheers John -- spambait 1aaaaaaa at coco.merseine.nu Z1aaaaaaa at coco.merseine.nu Please do not reply off-list