I can do :%s/ for replacing a string across a file, or :s/
To answer this question:
:40,50s/foo/bar/g
replace foo with bar in these lines between the 40th line and the 50th line(inclusive), when execute this command you can currently in any line.
:50,40s/foo/bar/g
also works, vim will ask you for comfirm and then do the replacement for you as if you have input the first command.
:,50s/foo/bar/g
replace foo with bar in these lines between the line you are currently in and the 50th line(inclusive). (if you are in a line AFTER the 50th line vim will ask for confirm again)
To clearity the difference between vim and the vrapper plugin of Eclipse:
Note that in varpper
:,50s/foo/bar/g command will NOT work.
:50,40s/foo/bar/g will work without asking for comfirmation.
(For Vrapper Version 0.74.0 or older).