$ Linux Command

Network

sshpass

Non-interactive SSH password authentication.

sshpasswordautomationnon-interactive

Additional Notes

sshpass provides non-interactive password authentication for SSH connections. It works by supplying the password to SSH via a pseudo-terminal (PTY), bypassing SSH's direct password prompt requirement. This is intended for scripting and automation where password authentication is unavoidable.

Because it exposes passwords on the command line or in environment variables, sshpass is less secure than key-based authentication. Its primary use case is automating connections to legacy systems that do not support public key authentication. Key-based authentication with ssh-agent is strongly preferred for production environments.

Syntax

sshpass [-f filename | -d num | -p password | -e] ssh [ssh_options] user@host [command]

Parameters

  • password: The password to use for SSH authentication.
  • user@host: The SSH destination.
  • command: Optional command to execute on the remote host.

Password Source Options

  • -p password: Provide the password directly on the command line (insecure, visible in process listing).
  • -f filename: Read the password from the first line of the specified file.
  • -d number: Read the password from file descriptor number.
  • -e: Read the password from the SSHPASS environment variable.
  • -P prompt: Specify the password prompt string to look for (default: password:).

Common SSH Options

  • -o StrictHostKeyChecking=no: Skip host key checking (use with caution).
  • -o UserKnownHostsFile=/dev/null: Do not save the host key.
  • -p port_num: Specify the SSH port (use SSH's -o Port=port syntax with sshpass).

Examples

sshpass -p 'mypassword' ssh alice@server.example.com

Connect using a password on the command line.

sshpass -f password.txt ssh alice@server.example.com

Read the password from a file.

export SSHPASS='mypassword'
sshpass -e ssh alice@server.example.com

Use the SSHPASS environment variable.

sshpass -p 'mypassword' ssh alice@server.example.com 'ls -la /tmp'

Execute a remote command with password authentication.

sshpass -p 'mypassword' scp file.txt alice@server.example.com:~/

Use sshpass with SCP for file transfer.

sshpass -f pass.txt rsync -av -e ssh ./dir/ alice@server.example.com:~/dir/

Use with rsync for automated backups.

Practical Notes

  • Password visible in process listings (ps aux) when using -p.
  • For production automation, always use SSH key authentication instead.
  • Some SSH configurations may reject password authentication; sshpass cannot override server-side settings.
  • The -o StrictHostKeyChecking=no option disables host key verification, reducing security.
  • On systems with SELinux, sshpass may need specific SELinux booleans enabled.
  • sshpass is not installed by default on many distributions; available via apt install sshpass or yum install sshpass.