>>161
man sshd
AUTHORIZED_KEYS FILE FORMAT
...
command="command"
Specifies that the command is executed whenever this key is used
for authentication. The command supplied by the user (if any) is
ignored. The command is run on a pty if the client requests a
pty; otherwise it is run without a tty. If an 8-bit clean chan-
nel is required, one must not request a pty or should specify
no-pty. A quote may be included in the command by quoting it
with a backslash. This option might be useful to restrict cer-
tain public keys to perform just a specific operation. An exam-
ple might be a key that permits remote backups but nothing else.
Note that the client may specify TCP and/or X11 forwarding unless
they are explicitly prohibited. Note that this option applies to
shell, command or subsystem execution.