GPFlags has one base command /gpflags ... from here, there are several sub commands.

Usage: /gpflags setclaimflag <flag> [<parameters>] This allows you to set a claim flag for a claim you are standing in. Parameters are may be required by said flag.

Usage: /gpflags setworldflag <flag> [<parameters>] This allows you to set a claim flag for an entire world. Some flags may not support this. Parameters are may be required by said flag.

Usage: /gpflags setserverflag <flag> [<parameters>] This allows you to set a claim flag for the entire server. Some flags may not support this. Parameters are may be required by said flag.

Usage: /gpflags setdefaultclaimflag <flag> [<parameters>] This allows you to set a claim flag for all claims (current or future claims). Parameters are may be required by said flag.

Usage: /gpflags setclaimflagplayer <player> <flag> [<parameters>] This allows you to set a claim flag for a claim a player is standing in. This can be run from either a player or console. Parameters are may be required by said flag.

Usage: /gpflags unsetclaimflag <flag> This allows you to unset a flag in a claim you are standing in. If the flag is set, it will be removed. If a world/server flag is set, this will just negate this flag in the claim.

Usage: /gpflags unsetworldflag <flag> This allows you to unset a world flag.

Usage: /gpflags unsetserverflag <flag> This allows you to unset a server flag.

Usage: /gpflags unsetdefaultclaimflag <flag> This allows you to unset a default claim flag.

Usage: /gpflags unsetclaimflagplayer <player> <flag> This allows you to unset a flag in a claim a player is standing in. If the flag is set, it will be removed. If a world/server flag is set, this will just negate this flag in the claim. This can be run from a player or console.

Usage: /gpflags listclaimflags This allows you to see a list of all flags in a claim you are standing in.

Usage: /gpflags allflags This sends a list of all possible flags, along with their flag type (ie: claim, server, world)

Usage: /gpflags reload This allows the user to reload the plugin.

All commands use the gpflags.command.<command> permission.
Example, the permission for the set flags command would be gpflags.command.setclaimflag

Each flag requires permission to use said flag.
All flags use the gpflags.flag.<flag> permssion.
Example, the permission for the NoEnterPlayer flag would be gpflags.flag.noenterplayer

gpflags.bypass = Makes a player immune to the limitations of flags like CommandBlackList, NoEnter, and NoFlight.
gpflags.bypass.fly = Makes a player immune to the limitations of the fly flags.
gpflags.bypass.exitcommand = Makes a player immune to the exit command flag.
gpflags.bypass.entercommand = Makes a player immune to the enter command flag.