How to get command line of UNIX process?

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

Solution 1:

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

Solution 2:

Does:

~$ 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).

Solution 3:

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!