Boolean options are switches that accept a true or false value. When the switch is set without an equals, it sets the option to true.

Option turned on
--switch

If the switch contains an equals, the value controls the enabled state of the option.

Enabled values

  • Any non-zero integer

  • The word on

  • The word yes

  • The word true

Disabled values

  • The integer zero

  • The word off

  • The word no

  • The word false

That is, the option can be toggled by setting it to integers (with zero being off), by setting it to "yes" or "no", or by setting it to "true" or "false". The word specifications are not case sensitive.

Option explicitly turned on
--switch=1
--switch=on
--switch=yes
--switch=TRUE
Option explicitly turned off
--switch=0
--switch=off
--switch=NO
--switch=false