How to create a bash script to check the SSH connection?

How to create a bash script to check the SSH connection?

My problem is that the remote machines are not very reliable, and they are not always up. I need a bash script that would check if the SSH connection is up. Before actually creating the keys for future use. EDIT: Another approach would be to use nmap (you won’t need to have keys or login-stuff):

How can I check for SSH authentication succeeded?

If you just want to check authentication, you may want to do ssh asimplecommand (using echo, hostname, or something as such) and check if you get the expected result. You may also want to launch ssh with -v option, and look for Authentication succeeded (at the debug1 log level).

Which is the best way to test a SSH connection?

Method 1: Use timeout with bash utility to test SSH connection. Shell Script Example. Method 2: Use nmap to test SSH connection. Shell script Example. Method 3: Use netcat or nc to test SSH connection. Shell Script Example. Method 4: Use SSH to check SSH connection. Shell Script Example. Method 5: Use telnet to test SSH connection.

How to write shell script to SSH to remote machine?

Install sshpass using, apt-get install sshpass then edit the script and put your linux machines IPs, usernames and password in respective order. After that run that script.

Where do I start sshd server in Linux?

OpenSSH server listens for connections from clients on TCP port number 22. The server is normally started at boot from /etc/init.d/ssh or /etc/init.d/sshd script. This page explains how to start sshd on Linux using the systemctl command. Open the terminal application. You must log in as root.

How to start and stop SSH server in Linux?

Start, stop, and restart the OpenSSH server on Linux. 1 CentOS/RHEL/Fedora Linux. To execute script or sshd service: sudo systemctl start ssh.service ## <– Linux start sshd ## sudo systemctl stop sshd. 2 Debian/Ubuntu Linux. 3 HP-UX Unix start/stop/restart sshd. 4 IBM AIX Unix users.

What’s the name of the SSH daemon in Linux?

OpenSSH SSH daemon is called sshd on Linux and used by ssh command. We use ssh and sshd for secure encrypted communications between two untrusted hosts over an insecure network or internet. OpenSSH server listens for connections from clients on TCP port number 22.

When to use SSH to execute a script?

SSH: Execute Remote Command or Script – Linux. This is quite a common task for Linux system administrators, when it is needed to execute some command or a local Bash script from a one Linux workstation or a server on another remote Linux machine over SSH.

How to run bash script on a remote server?

SSH: Run Bash Script on Remote Server. The equally common situation, when there is some Bash script on a Linux machine and it needs to connect from it over SSH to another Linux machine and run this script there.

How to execute SSH commands in multiple remote Linux machines?

There is are multiple ways to execute the commands or script in the multiple remote Linux machines. One simple & easiest way is via pssh (parallel ssh program) pssh: is a program for executing ssh in parallel on a number of hosts.

How to change script to SSH and run commands?

I’d change the script and would run the ssh command with the the command to execute. The && operator means that each command will be executed only if the previous command succeeded. If you want to run the command independently, you can change the && operator to ; instead.

What should the exit code of the ssh command be?

Just to be complete. Below ssh command should have an exit code of 0 on a successful connection and a non-zero value otherwise. #!/bin/sh IP=’192.168.0.’

Where do I put my SSH public key?

You need to put your SSH public key into the ~/.ssh/authorized_keys file on the remote host. Then you’ll be able to SSH to that host password-less. Alternatively you can use ssh-agent.

How can I SSH directly to a particular directory?

You can do the following: ssh -t xxx.xxx.xxx.xxx “cd /directory_wanted ; bash –login” This way, you will get a login shell right on the directory_wanted.

How to make Bash go to specific directories?

It is also explained over there how to put the code in ~/.bashrc so that every new shell opened will automatically have this new alias command. You can add new command to go to specific directories by modifying the code by adding more if conditions and different arguments. You can also pull the code from git over here.

How to check if my SSH daemon is running?

Try running something like monit, which will check to see if the daemon is running and restart it if it isn’t (giving you time to find the root problem behind sshd shutting down on you). Or is the network service troublesome? Try looking at man ifup. Does the Whole Damn Thing just like to shut down on you?

How to create a password for a SSH server?

You are now done. Now you can run the ssh using the above created alias sshLogin in terminal. This method is creating a hashed value of your password using RSA with public key of length 4096 which is very secure. First login into server 192.168.0.12 with a user and generate a pair of public keys using following command.

How to set up a password shell script?

You need to set it up first: Then invoke the SSH command from a script like this: This provides more flexibility, such as if you’re using a different locale or need to change the password, than solutions using expect. Now reload your changed .bashrc file by source ~/.bashrc