There are many times that I have no idea of where a command I use actually resides in the system. Sometimes I do, and what I'm calling is not the command that I know it should be, so ... How do you tell where the command that works from the command …

BASH command output to the variable has great examples of how to do this. Basically, it boils down to something like this:

variable=$(command)
variable=$(command [opotion...] arg1 arg2 ...)
variable=$(/path/to/command)

You can also use the "`" as well, with all the caveats of using it in bash entails …