grep for specific process in ps but not the grep command itself [duplicate]

Question

If I want to check if something is running, I do ps aux | grep flamethrower, expecting just to show the processes containing flamethrower in the name. This will always find at least one process, as grep flamethrower matches this criteria.

Is there some way to check for a specific process, in a cleaner way?

Answer 1

The usual way would be to use pgrep:

$ pgrep init
1
2215
6300
$ ps ax | grep init
    1 ?        Ss     6:41 /sbin/init
 2215 ?        Ss     1:54 init --user --restart --state-fd 26
 6300 ?        S      0:00 init --user --startup-event indicator-services-start
17522 pts/10   S+     0:00 grep --color=auto init

Note that you might need to use other tricks with pgrep as well, if you use it with watch and -f:

$ watch pgrep init -fa
Every 2.0s: pgrep init -fa                                                                                                                                                                                               
Wed Dec  3 19:19:47 2014

1 /sbin/init
2215 init --user --restart --state-fd 26
6300 init --user --startup-event indicator-services-start
18233 watch pgrep init -fa
18234 watch pgrep init -fa
18235 sh -c pgrep init -fa
$ watch pgrep [i]nit -fa
Every 2.0s: pgrep [i]nit -fa                                                                                                                                                                                           Wed Dec  3 19:20:42 2014

1 /sbin/init
2215 init --user --restart --state-fd 26
6300 init --user --startup-event indicator-services-start