How do I count specific processes on Mac OS X?

Question

Using a Mac, what would be the best way to count the number of instances of a particular process I am running? This is for a script I am writing to find the number of ffmpeg processes running on my machine.

Should I be using top here? ps aux|grep ffmpeg? What would be the best way to get the number?

Answer 1

grep -c will count occurrences:

count=`ps aux | grep -v "grep" | grep -c ffmpeg`
echo $count

Answer 2

ps aux | grep ffmpeg | wc -l will get you the number of processes that mention the phrase 'ffmpeg' you'll need to minus 1 on this value as ps aux | grep ffmpg is a process also.

Answer 3

You're looking for the program called "wc" -- "wc -l" will count lines for you.

"man wc" for details.

Answer 4

You can try the killall command on the Mac:

$ killall -s ffmpg
kill -TERM 20148
kill -TERM 20146
kill -TERM 20140

The -s means just list what you'd do, but don't actually kill any processes. Pipe it to wc, and you should get your result:

$ killall -s ffmpg | wc -l
3

In a shell script, you can do something like this:

num_of_processes=$(killall -s ffmpg | wc -l)

Answer 5

pgrep:

$ pgrep -c ffmpeg

If you don't use pgrep then mere grep might produce false positives.

To avoid it you could try -C option:

$ ps -C ffmpeg -o pid= | wc -l

Check that your ps version interprets it correctly.