how to run a script automatically in server soon after client system establish ssh connection with the server
for ex: suppose a user will logon to my computer from another system(connected via lan) using ssh connection. At that time, A script(python or shell) should be run automatically in my system to perform some validation?
How to run the script automatically in server system?
13 Answers
You can do so by adding the following parameter to your config file (/etc/ssh/sshd_config).
ForceCommand Forces the execution of the command specified by ForceCommand, ignoring any command supplied by the client and ~/.ssh/rc if present. The command is invoked by using the user's login shell with the -c option. This applies to shell, command, or subsystem execution. It is most useful inside a Match block. The command originally supplied by the client is available in the SSH_ORIGINAL_COMMAND environment variable. Specifying a command of “internal-sftp” will force the use of an in-process sftp server that requires no support files when used with ChrootDirectory.
An other option is to use the .ssh/rc files on a per user basis.
To use the ForceCommand method you just add ForceCommand /usr/bin/ownscript at the bottom of the file /etc/ssh/sshd_config (on the server).
The script looks like this:
#!/bin/bash
#Script file for ssh
#
#put your commands here
echo "test" > /tmp/test.txt
#
#exit by calling a shell to open for the ssh session
/bin/bashDon't forget to chmod the script sudo chmod +x /usr/bin/ownscript
You can create a /etc/ssh/sshrc file. See man 8 ssh.
If you want this for a single user, use ~/.ssh/rc.
Here is a sample /etc/ssh/sshrc that will notify you via dbus when someone logs in on your machine. Don't forget to chmod +x:
#!/bin/bash
ip=`echo $SSH_CONNECTION | cut -d " " -f 1`
notify-send -u CRITICAL "SSH connection from ${ip}" "User $USER just logged in from $ip"For execution of a script during logon, add it as a call from within the /etc/profile script. This is executed for every logon, not only for ssh logons.
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