You can determine the quest ID from Wowhead, e.g. https://www.wowhead.com/quest=53068/operation-hook-and-line which is 53068.

/script print( IsQuestFlaggedCompleted( 1234 ) )

Learn OOX quest status ∞

was us.battle.net/wow/en/forum/topic/6412974897#5 (not archived)

Tested and works for:

• World of Warcraft 5 (MoP) – 5.0.4

• World of Warcraft 8 (BfA) – 8.0.1

/run local z,t,s={[836]='The Hinterlands',[648]='Tanaris',[25476]='Feralas'},GetQuestsCompleted();for c,v in pairs(z) do if t[c] then s='' else s=' not' end print('You have'..s,'found OOX in',v) end