Do you frequently reboot devices and want to execute a command (or open a shell) once it reboots?
Then use sshwait!
sshwait is a transparent wrapper for ssh which will wait (indefinitely) for the host to be available before executing ssh itself.
Once the host can be reached via ssh, sshwait will execute ssh with the exact arguments that sshwait was provided. This means you can reboot a device and execute a command the moment sshd comes back up.
sshwait user@example.com -p 10022 echo "Hello, World!"
or you can start an interactive shell as usual
sshwait user@example.com -p 10022
If you've already specified the user and port for example.com in $HOME/.ssh/config then you don't need to specify them. Since sshwait simply calls ssh, your local configuration will be used if you don't provide a user or port, just like normal.
sshwait example.com
No dependencies other than python3 are needed. To install the script, simply copy sshwait to somewhere on your local or global $PATH and ensure it's marked as executable. I personally have mine located in $HOME/.local/bin.