When you are trying to use a command and it is not working, these cli tools are handy.
whereis <command> : should return the location of the command
which <command> : returns the location attached to the command
locate <name> : is a rather quick find (not necesarily)
of course, using these outputs along with know what is in your PATH variable should give you a clue to finding a solution.
The examples i gave are the short short short version, you would do better reading the man pages on them to understand better what they do