bash -gt command with pgrep & wc

Question

I'm trying to run [ pgrep mongo | wc -l -gt 2] to see if there are more than 2 mongo processes running, but I keep getting this error -bash: [: missing `]'

I feel like I'm missing something simple here. Thanks!

Answer 1

You need command substitution and a space before ]:

[ $(pgrep mongo | wc -l) -gt 2 ]

$(...) is the syntax for command substitution

Answer 2

Besides using command substitution, it is a good idea to use arithmetic expression in that case:

(( $(pgrep mongo | wc -l) > 2 ))