Secure Shell Commands

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The following table summarizes the main Secure Shell commands.

Table 2-4 Commands in Secure Shell

Man Page for Command	Description
`ssh`(1)	Logs a user in to a remote machine and securely executes commands on a remote machine. The `ssh` command enables secure encrypted communications between two untrusted hosts over an insecure network. X11 connections and arbitrary TCP/IP ports can also be forwarded over the secure channel.
`sshd`(1M)	The daemon for Secure Shell. The daemon listens for connections from clients and enables secure encrypted communications between two untrusted hosts over an insecure network.
`ssh-add`(1)	Adds RSA or DSA identities to the authentication agent, `ssh-agent`. Identities are also called keys.
`ssh-agent`(1)	Holds private keys that are used for public key authentication. The `ssh-agent` program is started at the beginning of an X-session or a login session. All other windows and other programs are started as clients of the `ssh-agent` program. Through the use of environment variables, the agent can be located and used for authentication when users use the `ssh` command to log in to other systems.
`ssh-keygen`(1)	Generates and manages authentication keys for Secure Shell.
`ssh-keyscan`(1)	Gathers the public keys of a number of Secure Shell hosts. Aids in building and verifying `ssh_known_hosts` files.
`ssh-keysign`(1M)	Used by the `ssh` command to access the host keys on the local host. Generates the digital signature that is required during host-based authentication with Secure Shell v2. The command is invoked by the `ssh` command, not by the user.
`scp`(1)	Securely copies files between hosts on a network over an encrypted `ssh` transport. Unlike the `rcp` command, the `scp` command prompts for passwords or passphrases if password information is needed for authentication.
`sftp`(1)	An interactive file transfer program that is similar to the `ftp` command. Unlike the `ftp` command, the `sftp` command performs all operations over an encrypted `ssh` transport. The command connects, logs in to the specified host name and then enters interactive command mode.

The following table lists the command options that override Secure Shell keywords. The keywords are specified in the ssh_config and sshd_config files.

Table 2-5 Command-Line Equivalents for Secure Shell Keywords

Keyword	`ssh` Command-Line Override	`scp` Command-Line Override
`BatchMode`		`scp -B`
`BindAddress`	`ssh -b` `bind-addr`	`scp -a` `bind-addr`
`Cipher`	`ssh -c` `cipher`	`scp -c` `cipher`
`Ciphers`	`ssh -c` `cipher-spec`	`scp -c` `cipher-spec`
`Compression`	`ssh -C`	`scp -C`
`DynamicForward`	`ssh -D` `SOCKS4-port`
`EscapeChar`	`ssh -e` `escape-char`
`ForwardAgent`	`ssh -A` to enable `ssh -a` to disable
`ForwardX11`	`ssh -X` to enable `ssh -x` to disable
`GatewayPorts`	`ssh -g`
`IPv4`	`ssh -4`	`scp -4`
`IPv6`	`ssh -6`	`scp -6`
`LocalForward`	`ssh -L` `localport:remotehost:remoteport`
`MACS`	`ssh -m` `MAC-spec`
`Port`	`ssh -p` `port`	`scp -P` `port`
`Protocol`	`ssh -2` for v2 only
`RemoteForward`	`ssh -R` `remoteport:localhost:localport`