mktemp -- make a unique file name
The root (prefix) for the generated filename.
Mktemp returns a unique filename string which may be used to create a temporary file name. The string is the concatenation of three elements: the input argument, the process id, and a final character which changes on each call.
1. Create a unique filename with the root "sav" in the logical directory "tmp".
savefile = mktemp ("tmp$sav")
Since some time may elapse between the creation of the filename and the creation of a file with that name, there is no guarantee that the name will still be unique when it is actually used, however the algorithm used to generate the name makes filename collisions unlikely.