-bash: command not found appears every time I just recently discovered what terminal was. I started using it today and every time I try a command (like shh) it says that the command was not found. I was instructed to type in echo $PATH and this is what I got 

/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin


How can I fix this? I know mostly nothing about terminal or how to use it.
I wonder if the command you want is ssh , not shh.  Are you trying to connect to another computer? As Doc G points out, your PATH looks fine.