not found

Cause
This message indicates that the Bourne shell could not find the program name given
as a command.
Action
Check the form and spelling of the command line. If that data looks correct, do a
echo $PATH to see if the user’s search path is correct. When communications are
garbled, it is possible to unset a search path to such an extent that only built-in shell
commands are available. Below is a command to reset a basic search path:
$ PATH=/usr/bin:/usr/ccs/bin:/usr/openwin/bin:.
If the search path looks correct, check the directory contents along the search path for
missing programs or directories that are not mounted.

Not login shell

Cause
This message results when a user tries to use the logout(1) command from a shell
other than the one started at login time.
Action
To quit a non-login shell, use the exit(1) command. Continue doing so until you
have logged out.

Not on system console

Cause
A user tried to use the login(1) command to a system as the superuser (uid=0,
which is not necessarily root) from a terminal other than the console.
Action
Log in to that system as a normal user, then run su(1M) to become superuser. To
allow superuser logins from any terminal, comment out the CONSOLE line in
/etc/default/login (this is not recommended for security reasons).