L IMITATION OF F UNDS (APR 1984) (a) The parties estimate that performance of this contract will not cost the Govern-ment more than (1) the estimated cost speci-fied in the Schedule or, (2) if this is a cost-sharing contract, the Governmentâs share of the estimated cost specified in the Schedule.
The research upholds that until and till are generally accepted. As for 'til, always make sure to use the apostropheand because the word is not warmly accepted in all quarters, handle it with care. I was certain proper use of the contraction for the word until is 'til; however, I often see it spelled till.
do {} until ($false) is an infinite loop; it'll only exit if you use something like break, return or throw from inside the loop body. do { } until ($true) would execute the loop body exactly once (which would make the loop rather pointless.) It looks like what you intended to do was wait for a file to exist.