SSH automation in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of SSH command with remote script

What is the output of this bash script that uses SSH to run a remote command?

Bash Scripting

ssh user@remotehost 'echo Hello from $(hostname)'

A Hello from $(hostname)

B ssh: Could not resolve hostname remotehost: Name or service not known

C Hello from localmachine

D Hello from remotehost

💡 Hint

The command runs on the remote host, so hostname is evaluated there.

The $(hostname) runs on the remote machine, so the output shows the remote hostname.

📝 Syntax

intermediate

Correct SSH key usage in bash script

Which option correctly uses an SSH private key file to connect to a remote server in a bash script?

A ssh --key ~/.ssh/id_rsa user@host

B ssh -i ~/.ssh/id_rsa user@host

C ssh -keyfile ~/.ssh/id_rsa user@host

D ssh -k ~/.ssh/id_rsa user@host

💡 Hint

The correct option uses the -i flag for identity file.

The -i option specifies the private key file for SSH authentication.

🔧 Debug

advanced

Why does this SSH command fail?

This bash script tries to copy a file to a remote server using SSH and SCP but fails. Why? scp /local/path/file.txt user@remotehost:/remote/path/ Options:

A The remote path does not exist or user has no write permission

B The local file path is incorrect

C The SSH server is not running on remotehost

D The scp command syntax is invalid

💡 Hint

Check permissions and existence of remote directory.

If the remote directory does not exist or user lacks write permission, scp fails.

🚀 Application

advanced

Automate running multiple commands over SSH

You want to run these two commands on a remote server via SSH in one connection: 1. cd /var/log 2. ls -l Which option correctly does this in a bash script?

A ssh user@host 'cd /var/log && ls -l'

B ssh user@host 'cd /var/log ls -l'

C ssh user@host 'cd /var/log; ls -l'

D ssh user@host 'cd /var/log | ls -l'

💡 Hint

Separate commands with semicolon or && to run sequentially.

Using semicolon or && runs commands sequentially; pipe (|) sends output of first as input to second.

🧠 Conceptual

expert

Understanding SSH agent forwarding security

What is the main security risk of enabling SSH agent forwarding when automating remote commands?

A A compromised remote server can use your SSH keys to access other servers without your passphrase

B Your private key file is copied to the remote server

C Your SSH password is sent in plain text over the network

D Agent forwarding disables encryption of SSH traffic

💡 Hint

Agent forwarding allows remote servers to use your keys temporarily.

Agent forwarding lets the remote server use your SSH keys to connect elsewhere, so if compromised, it can misuse your keys.