easily strace all your apache processes

ps auxw | grep sbin/apache | awk '{print"-p " $2}' | xargs strace
This one-liner will use strace to attach to all of the currently running apache processes output and piped from the initial "ps auxw" command into some awk.
Sample Output
ps auxw | grep sbin/apache | awk '{print"-p " $2}' | xargs strace
Process 7313 attached - interrupt to quit
Process 7395 attached - interrupt to quit
Process 7396 attached - interrupt to quit
Process 7397 attached - interrupt to quit
Process 7398 attached - interrupt to quit
Process 7399 attached - interrupt to quit
Process 7401 attached - interrupt to quit
Process 7403 attached - interrupt to quit
Process 7448 attached - interrupt to quit
Process 7468 attached - interrupt to quit
Process 7469 attached - interrupt to quit
attach: ptrace(PTRACE_ATTACH, ...): No such process
[pid  7313] select(0, NULL, NULL, NULL, {0, 48000} <unfinished ...>
[pid  7395] poll([{fd=11, events=POLLIN}, {fd=10, events=POLLIN}, {fd=9, events=POLLIN}, {fd=8, events=POLLIN}, {fd=7, events=POLLIN}, {fd=6, events=POLLIN}, {fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=85, events=POLLIN}, {fd=19, events=POLLIN}], 10, -1 <unfinished ...>
[pid  7396] semop(1572864, {{0, -1, SEM_UNDO}}, 1 <unfinished ...>
[pid  7397] semop(1572864, {{0, -1, SEM_UNDO}}, 1 <unfinished ...>
[pid  7398] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7399] semop(1572864, {{0, -1, SEM_UNDO}}, 1 <unfinished ...>
[pid  7401] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7403] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7448] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7468] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7469] poll([{fd=15, events=POLLIN}, {fd=19, events=POLLIN}], 2, -1 <unfinished ...>
[pid  7313] <... select resumed> )      = 0 (Timeout)
[pid  7313] gettimeofday({1300139401, 36665}, NULL) = 0
[pid  7313] waitpid(-1, 0xffdc0a68, WNOHANG|WSTOPPED) = 0
[pid  7313] select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)
[pid  7313] gettimeofday({1300139402, 39688}, NULL) = 0
[pid  7313] waitpid(-1, 0xffdc0a68, WNOHANG|WSTOPPED) = 0
[pid  7313] select(0, NULL, NULL, NULL, {1, 0} <unfinished ...>
Process 7313 detached
Process 7395 detached
Process 7396 detached
Process 7397 detached
Process 7398 detached
Process 7399 detached
Process 7401 detached
Process 7403 detached
Process 7448 detached
Process 7468 detached
Process 7469 detached

7
By: px
2011-03-14 21:45:22

7 Alternatives + Submit Alt

What Others Think

Why the inclusion of the the time of the running process only to use awk to separate out on the fs (:) to get the pid? On CentOS (tested on 5.5) this provides the same results: ps auxw | grep sbin/httpd | awk '{print $2}' | awk ' {print "-p "$1}' | xargs strace
mrlinsky · 379 weeks and 2 days ago
Actually, this works as well on the same test env: ps auxw | grep sbin/httpd | awk '{print"-p " $2}' | xargs strace
mrlinsky · 379 weeks and 2 days ago
Thanks @mrlinsky, I will update the command. I just put together a few bits and forgot to get rid of the extras while I tested it. :)
px · 379 weeks and 2 days ago
there, i shortened it for ya'll from 4 command pipe to 3. strace $(pidof httpd | sed 's/\([0-9]*\)/\-p \1/g')
layer3switch · 379 weeks and 1 day ago
@layer3switch, thank you kindly.
px · 379 weeks and 1 day ago
Shorter: sh -c "strace -p{$(pgrep -d, apache)}"
akg240 · 379 weeks and 1 day ago
@akg240, that wouldn't work for fork() process as there is no way of knowing which calls are attached to which pid. the whole point of separate "-p" per pid is to associate calls per pid. also "sh -c" must include following string enclosed using single quote, not double quote.
layer3switch · 379 weeks ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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