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

By: px

2011-03-14 21:45:22

awk grep ps xargs awk token ps tokenizer

9 Alternatives + Submit Alt

easily strace all your apache *child* processes

Like the original version except it does not include the parent apache process or the grep process and adds "sudo" so it can be run by user.
This is sample output - yours may be different.
3

ps h --ppid $(cat /var/run/apache2.pid) | awk '{print"-p " $1}' | xargs sudo strace

colinmollenhour · 2012-03-21 01:59:41 4
easily strace all your apache processes

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This is sample output - yours may be different.
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ps auxw | grep -E 'sbin/(apache|httpd)' | awk '{print"-p " $2}' | xargs strace -F

gormux · 2016-08-04 10:59:58 14
Strace all signals processes based on a name ( The processes already started... ) with bash built-in

Especially for sysadmins when they don't want to waste time to add -p flag on the N processes of a processname. In the old school, you did ; pgrep processname and typing strace -f -p 456 -p 678 -p 974... You can add -f argument to the function. That way, the function will deal with pgrep to match the command-line. Example : processname -f jrockit
This is sample output - yours may be different.
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sputnick · 2009-12-03 00:04:39 9
easily strace all your apache processes

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This is sample output - yours may be different.
1

ps auxw | grep sbin/apache | awk '{print"-p " $2}' | xargs strace -f

msealand · 2013-02-19 19:14:57 5
easily strace all your apache processes
This is sample output - yours may be different.
0

pgrep -f /usr/sbin/httpd | awk '{print"-p " $1}' | xargs strace

savagemike · 2015-06-10 22:55:35 12

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 · 704 weeks ago

Actually, this works as well on the same test env: ps auxw | grep sbin/httpd | awk '{print"-p " $2}' | xargs strace

mrlinsky · 704 weeks 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 · 704 weeks 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 · 703 weeks and 6 days ago

@layer3switch, thank you kindly.

px · 703 weeks and 6 days ago

Shorter: sh -c "strace -p{$(pgrep -d, apache)}"

akg240 · 703 weeks and 6 days 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.

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