Mac Script “purge”

Last time i using this script at MBP (MacBook Pro) everything ok and i can free my computer inactive ram, but it doesn’t work with my iMac, i have no idea why the script are doesn’t work? When I enter purge via Terminal, I get a “command not found” response.

I have keep trying and do research in internet only found i forgot to install Xcode for my iMac, after install the Xcode going good .. yeah ~