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Is it possible to grab the command line that was used to invoke a process on Mac OS X?

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ps --pid $PID -o args= That's what I use, anyway... – yardena Jul 26 '11 at 17:52
The Mac equivalent of that command is: ps -p <pid> -o args= – Nate May 7 '13 at 17:00
up vote 9 down vote accepted

ps ax shows you the command line of all running processes; you can grep for the pid you want.

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@mark4o Or simply ps awux | cat, as ps -w will not limit the number of columns to display when output is not stdout, such as when piped to another command. – jtimberman Aug 22 '09 at 21:06
Why does this happen every week? "Warning: bad ps syntax, perhaps a bogus '-'? See"; and "Note that "ps -aux" is distinct from "ps aux". The POSIX and UNIX standards require that "ps -aux" print all processes owned by a user named "x", as well as printing all processes that would be selected by the -a option. If the user named "x" does not exist, this ps may interpret the command as "ps aux" instead and print a warning. This behavior is intended to aid in transitioning old scripts and habits. It is fragile, subject to change, and thus should not be relied upon." – Hello71 Jul 27 '11 at 16:47
I don't know, Hello71. I corrected my two-year-old answer for you. – Bkkbrad Aug 18 '11 at 18:31


~$ ps ax | grep "ntp"
   57   ??  Ss     0:04.66 /usr/sbin/ntpd -c /private/etc/ntp.conf -n
 3104 s000  S+     0:00.00 grep ntp

do what you need it to (change ntp to the program you are interested in)? This usually gives me the command-line arguments of running processes (I use to check what Launchd used when running a system daemon for example).

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cat /proc/$PROCESSNUMBER/cmdline | tr '\0' '\n'

Allthough it's Linux specific, it gets the commandline of process numbered $PROCESSNUMBER straight from the kernel (the /proc/$PROCESSNUMBER/cmdline part) and makes it readable by putting each argument on a separate line by translating (with tr -token replace) the \0's into newlines (\n).

This line only works if you put a real processnumber of a running process (you can find one by running the command ps -ef) in the $PROCESSNUMBER part!

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The original poster asked for Mac OS X (which out of the box does not have procfs) – Andre Holzner Feb 29 '12 at 22:45
Or xargs -0 < /proc/PID/cmdline – Bash Sep 12 '12 at 23:22

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