Process status, information about processes running in memory.
Syntax ps [-aCcefhjlMmrSTuvwx] [-O fmt] [-o fmt] [-p pid] [-t tty] [-U username] ps [-L] Options -a Display information about other users' processes as well as your own. -c Change the `command' column output to just contain the executable name rather than the full command line. -C Change the way the cpu percentage is calculated by using a `raw' cpu calculation that ignores `resident' time (this normally has no effect). -e Display the environment as well. -f Show commandline and environment information about swapped out processes. This option is honored only if the uid of the user is 0. -h Repeat the information header as often as necessary to guarantee one header per page of information. -j Print information associated with the following keywords: user, pid, ppid, pgid, sess, jobc, state, tt, time and command. -L List the set of available keywords. -l Display information associated with the following keywords: uid, pid, ppid, cpu, pri, nice, vsz, rss, wchan, state, tt, time and command. -M Print the threads corresponding to each task. -m Sort by memory usage, instead of by process ID. -O Add the information associated with the space or comma separated list of keywords specified, after the process ID, in the default information display. Keywords may be appended with an equals (`=') sign and a string. This causes the printed header to use the specified string instead of the standard header. -o Display information associated with the space or comma separated list of keywords specified. Keywords may be appended with an equals (`=') sign and a string. This causes the printed header to use the specified string instead of the standard header. -p Display information associated with the specified process ID. -r Sort by current cpu usage, instead of by process ID. -S Change the way the process time is calculated by summing all exited children to their parent process. -T Display information about processes attached to the device asso- ciated with the standard input. -t Display information about processes attached to the specified terminal device. -U Display the processes belonging to the specified username. -u Display information associated with the following keywords: user, pid, %cpu, %mem, vsz, rss, tt, state, start, time and command. The -u option implies the -r option. -v Display information associated with the following keywords: pid, state, time, sl, re, pagein, vsz, rss, lim, tsiz, %cpu, %mem and command. The -v option implies the -m option. -w Use 132 columns to display information, instead of the default which is your window size. If the -w option is specified more than once, ps will use as many columns as necessary without regard for your window size. -x Display information about processes without controlling termi- nals.
Since ps cannot run faster than the system and is run as any other scheduled process, the information it displays can never be exact.
“A human being is a part of the whole, called by us "Universe”, a part limited in time and space" ~ Albert Einstein
ps man page - Apple.com
kill - Stop a process from running
lsof - List open files
opensnoop - Snoop file opens as they occur
top - Display process information