Killall command unavailable


I’m training with the lesson 4 of the terminal tutorial and when I typed killall sleep, the system output
killall command not found

Is it possible to add it or if not to change the tutorial ?

Here to second this as it appears to still be a problem months later. When trying to use killall, it says command not found
It also says pidof should display a process ID but it never displays anything when I run it.
pstree also says command not found.

Just had the same problem. I can use pkill command instead though which does the same thing.
Perhaps a “yum install psmisc” is required on the server to install killall program along with pstree.