Negate a command return value condition in bash

Question

I tried to negate the following condition:

if pgrep "$NAME" >> /dev/null; then
    # stuff
fi

At first I tried a syntax, what you can found in this thread.

if ! [[ pgrep "$NAME" >> /dev/null ]]; then
    # stuff
fi

While this syntax is perfect if you want to compare variables and literals, however in my case it will fail with the following error:

watchdog: line 58: conditional binary operator expected

watchdog: line 58: syntax error near `"$NAME"'

watchdog: line 58: ` if ! [[ pgrep "$NAME" >> /dev/null ]]; then'

Answer 1

Simply use ! to to check if it failed:

if ! pgrep "$NAME" >> /dev/null; then
    # stuff
fi