Go into System, Character Configuration, UI Settings, HUD, there is a toggle option to display Duty List. I think in another thread (or even this one?) someone mentioned that there is a macro you can use, so there is some / command of sorts, dunno what that it. But, you can do this.
Edit!:
http://na.finalfantasyxiv.com/lodest.../text_command/
Select Other from the list on the left. And then find /hud
You evidently use "/hud DutyList" or "/hud dlist"
/hud USAGE:
/hud [UI element] [subcommand]
→Toggle on/off various UI elements.
>>UI Elements:
Target Bar
TargetBar, tbar
Focus Target Bar
FocusTarget, ftarget
Party List
PartyList, plist
Enemy List
EnemyList, elist
Parameter Bar
ParamBar, param
Minimap
Minimap, mmap
Main Menu
MainMenu, mmenu
Server Info
ServerInfo, server
Gil
Gil, gil
Inventory Grid
InventoryGrid, igrid
Duty List
DutyList, dlist
Item Help
ItemHelp, ihelp
Action Help
ActionHelp, ahelp
LimitGauge
LimitGauge, lgauge
Experience Bar
ExpBar, ebar
Status Effects
StatusEffects, sfx
Alliance List 1
AllianceList1, alist1
Alliance List 2
AllianceList2, alist2
>>Subcommands:
on Show element.
off Hide element.
Toggle between on/off when no subcommand is specified.