SSH, The Secure Shell: The Definitive Guide, 2nd Edition

Environment Variables

Variable	Set by	In	Meaning
SSH_ASKPASS	ssh user	OpenSSH	Path to askpass program
SSH_AUTH_SOCK	ssh-agent	OpenSSH	Path to socket
SSH2_AUTH_SOCK	ssh-agent	Tectia	Path to socket
SSH_CLIENT	sshd	OpenSSH	Client socket info
SSH2_CLIENT	sshd	Tectia	Client socket info
SSH_CONNECTION	sshd	OpenSSH	Client and server socket info
SSH_ORIGINAL_COMMAND	sshd	OpenSSH	Client’s remote command string
SSH_ORIGINAL_COMMAND2	sshd	Tectia	Client’s remote command string
SSH_SOCKS_SERVER	ssh user	Tectia	SOCKS firewall information
SSH_TTY	sshd	OpenSSH	Name of allocated TTY
SSH2_TTY	sshd	Tectia	Name of allocated TTY