It looks that at one point or another are overwriting the default
PATH environment variable. The type of errors you have, indicates that
PATH does not contain e.g.
/bin, where the commands (including bash) reside.
One way to begin debugging your bash script or command would be to start a subshell with the
bash --login -x
This will show you every command, and its arguments, which is executed when starting that shell.
Also very helpful is show
PATH variable values:
If you run this:
most commands should start working - and then you can edit
~/.bash_profile instead of
~/.bashrc and fix whatever is resetting
PATH there. Default
PATH variable values for root and other users is in