You corrupted your PATH variable definition. Without any indication of which method you choosed to modify it, I will make the hypothesis that you
modified it within your ~/.bash_profile.
To recover from this situation, you will have to come back to a working shell environment and then try to fix correctly and test your ~/.bash_profile.
Recovery of a working ~/.bash_profile: none
Remove your ~/.bash_profile and create a backup of it.
Since your PATH is not trustable, don't use it (use the full path of mv):
/bin/mv ~/.bash_profile ~/.bash_profile.bak
Open a new Terminal window, within this one, every command should be
found. Check that you recovered a working PATH:
echo $PATH
If you find it easier, after this check, you could restart your session so
that any new shell will get a working PATH.
Analyze what is wrong in your ~/.bash_profile
grep PATH ~/.bash_profile.bak
Fix and test it
Rather to fall back again with an unfunctionnal PATH, use the backup
file of your ~/.bash_profile to fix it there it and test it.
To test it enter:
. ~/.bash_profile.bak
echo $PATH
Put back in place the validated /.bash_profile
Once you are satisfied, and you checked you have access to all your
commands:
mv ~/.bash_profile.bak ~/.bash_profile
and if you want to use it immediatly without restarting your full session,
just enter:
. ~/.bash_profile