The answer to the "knowing what options are" is auto-complete [0], [1]. (Almost) nobody knows all the commands by heart. [0] http://www.cisco.com/c/en/us/td/do

The answer to the "knowing what options are" is auto-complete [0], [1]. (Almost) nobody knows all the commands by heart. [0] http://www.cisco.com/c/en/us/td/docs/security/fwsm/fwsm31/command/reference/fwsm_ref/usecli.html#wp1046291 http://www.cisco.com/c/en/us/td/docs/security/fwsm/fwsm31/co... [1] http://zsh.sourceforge.net/Doc/Release/Completion-System.html http://zsh.sourceforge.net/Doc/Release/Completion-System.htm...