Hard terms; “rather rough treatment;” exacting. Lines mean lot or allotment (measured out by a line measure), as, “The lines have fallen to me in pleasant places; yea, I have a goodly heritage,” i.e. my allotment is excellent. Hard lines = an unfavourable allotment (or task).
“That was hard lines upon me, after I had given up everything.”
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894