ssh-agent Command Line Options

The syntax for ssh-agent is:

ssh-agent [-c] [-d debug_level] [-h] [k] [-s] [-t timeout] [-V] [command]

Options are available in both a single-character form (such as ‑o) and a descriptive equivalent (‑‑option). Single characters are shown here. To view the descriptive equivalents, use the ‑h command line option.

-c

Forces the shell to be csh. By default ssh-agent uses the SHELL environment variable to determine which shell to invoke. This option overrides the default behavior.

-d debug_level

Sets the debug level. Increasing the value increases the amount of information displayed. Use 1, 2, 3, or 99. (Values 4-98 are accepted, but are equivalent to 3.)

-h

Displays a brief summary of command options.

-k

Kills the current agent (given by the SSH_AGENT_PID environment variable).

-s

Forces the shell to be sh. By default ssh-agent uses the SHELL environment variable to determine which shell to invoke. This option overrides the default behavior.

-t timeout

Sets a default timeout for any key added to the agent. Keys are deleted after the specified timeout. By default keys have no timeout limit, which is equivalent to setting a timeout value of zero(0). (You can also specify timeouts when you add keys by using the ssh-add -t option, which overrides this setting.)

By default, the timeout value is set in minutes. You can specify other units using this syntax:

n<unit>[n<unit>…]

Where unit can be: s (seconds), m (minutes), h (hours), d (days), or w (weeks). (Upper or lower case units are both accepted with the same meaning.) For example:

3600s = 3600 seconds (1 hour)

2w = 2 weeks

2d4h = 2 days and 4 hours

-V

Displays product name and version information and exits. If other options are specified on the command line, they are ignored.