The GNU time program for measuring cpu resource usage The `time' command runs another program, then displays information about the resources used by that program, collected by the system while the program was running. You can select which information is reported and the format in which it is shown, or have `time' save the information in a file instead of display it on the screen. The resources that `time' can report on fall into the general categories of time, memory, I/O, and IPC calls. The GNU version can format the output in arbitrary ways by using a printf-style format string to include various resource measurements.