Why can't pgrep find this process?

Question

If I execute the following, which is just a long command that will wait forever

grep 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa abcd'

then pgrep -f can't find the process, if I search for abcd which is contained in the last segment of the long command.

ps auxww|grep abcd finds the process, but I can't use it in a script, as it also finds the grep process self.

If you remove just one a then pgrep -f abcd can find the process, but I have very long command with arguments, so I have run into this pgrep limitation.

Question

What is the correct way to check for such process based on the unique string abcd?

Answer 1

Your edited command is found by either of these commands:

pgrep -f abcd

or even:

ps uxww | grep '[a]bcd'

Answer 2

Let me try that...

$ grep 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa abcd'

Now in another terminal window:

$ pgrep grep
1842

Found it, or at least some grep process:

$ ps -f $(pgrep grep)
  UID   PID  PPID   C STIME   TTY           TIME CMD
  501  1842  1836   0  8:59AM ttys004    0:00.00 grep aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa abcd

Yup, that was the process found.

Let's try this:

$ pgrep -f 'abcd'
1842

Seems to work for me.