Basic - Shell Builtins

alias
echo
 expr
 printf
sleep

The sleep command suspends execution of a process for at least the interval specified. The sleep instruction suspends the calling process for at least the specified number of seconds (the default), minutes, hours or days.

Usage:
sleep number[suffix]
or:
sleep option

Suffix:
s (seconds)
m (minutes)
h (hours)
d (days)



 test
true and false
unset
wait
 yes