From command reference:
Code:
/crosshotbar, /chotbar
USAGE: /crosshotbar [subcommand] [number]
Edit and configure cross hotbar settings.
>>Subcommands
set "action name" [number] [slot name] - Set the specified action to [slot name] in cross hotbar [number]. If [slot name] is omitted, the action will be set to the slot with the lowest available number. If both [number] and [slot name] are omitted, the action will be set to the slot with the lowest number available on the cross hotbar with the lowest number available.
change [number] - Replace current cross hotbar with cross hotbar [number].
copy [class 1] [number 1] [class 2] [number 2] - Copy the contents of [class 1] cross hotbar [number 1] to the [class 2] cross hotbar [number 2].
display [number] on - Display cross hotbar [number].
display [number] off - Hide cross hotbar [number].
display [number] - Toggle on/off cross hotbar [number].
share [number] on - Make cross hotbar [number] shared.
share [number] off - Unshare cross hotbar [number] and assign it to your current class/job.
share [number] - Toggle between on/off.
remove [number 1] [slot name] - Remove the action assigned to [slot name] on cross hotbar [number]. Replace [slot name] with "all" to remove all actions from cross hotbar [number].
>>Slot Names:
LT + ← LDL(LD1) RT + ← RDL(RD1)
LT + ↑ LDU(LD2) RT + ↑ RDU(RD2)
LT + → LDR(LD3) RT + → RDR(RD3)
LT + ↓ LDD(LD4) RT + ↓ RDD(RD4)
LT + X LAL(LA1) RT + X RAL(RA1)
LT + Y LAU(LA2) RT + Y RAU(RA2)
LT + B LAR(LA3) RT + B RAR(RA3)
LT + A LAD(LA4) RT + A RAD(RA4)
Currently this does not function with Pet and Companion actions, which are no macro-able according to command reference::
Code:
/action, /ac
USAGE: /action "action name" "PC name"
Uses an action on the specified PC.
Uses current target when not specified.
This cannot be used with actions you have not yet learned, or when restricted by other factors.
/petaction, /pac
USAGE: /petaction "pet action name" "PC name"
Uses a pet action on the specified PC.
Uses current target when not specified.
This cannot be used with pet actions you have not yet learned, or when restricted by other factors.
/companionaction, /cac
USAGE: /companionaction "companion action name"
Uses a companion action. The target of companion actions cannot be specified.
This cannot be used with companion actions you have not yet learned, or when restricted by other factors.
Once this is addressed, pet classes will be fully flexible via the macro system.
Please and thank you 
P.S. Initially brought up in this thread.