Environment Variables Variable Set By In Meaning SSH_AUTH_SOCK ssh-agent SSH1, OpenSSH Path to socket SSH2_AUTH_SOCK ssh-agent SSH2 Path to socket SSH_CLIENT sshd SSH1, OpenSSH Socket info SSH2_CLIENT sshd SSH2 Socket info SSH_ORIGINAL_COMMAND sshd SSH1 Client's remote command string SSH_SOCKS_SERVER sshd SSH2 SOCKS firewall information SSH_TTY sshd SSH1, OpenSSH Name of allocated TTY SSH2_TTY sshd SSH2 Name of allocated TTY