Problem with file path

[Mircea Draghicescu]

See below. Thanks.
Mircea

~/temp 87: ghc -o main main.hs
ghc: module version changed to 1; reason: no old .hi file
~/temp 89: mkdir a
~/temp 90: mkdir a/b
~/temp 91: cp main.hs a/b
~/temp 92: ghc -o main a/b/main.hs
ghc: module version changed to 1; reason: no old .hi file
cp: cannot create regular file `b/Main.hi': No such file or directory
~/temp 93: mkdir b
~/temp 94: ghc -o main a/b/main.hs
ghc: module version changed to 1; reason: no old .hi file
~/temp 95: ls b
Main.hi
~/temp 96: