The
time utility executes and times
utility. After the
utility finishes,
time writes the total time elapsed, the time consumed by system overhead, and the time used to execute
utility to the standard error stream. Times are reported in seconds.
Available options:
-c
Displays information in the format used by the
time builtin of
csh(1).
-l
Lists resource utilization information. The contents of the utility process' rusage structure are printed; see below.
-p
The output is formatted as specified by IEEE Std 1003.2-1992 (“POSIX.2”).
Some shells, such as
csh(1) and
ksh(1), have their own and syntactically different builtin version of
time. The utility described here is available as
/usr/bin/time to users of these shells.
Resource Utilization
If the
-l option is given, the following resource usage information is displayed in addition to the timing information:
maximum resident set size
average shared memory size
average unshared data size
average unshared stack size
voluntary context switches
involuntary context switches
Resource usage is the total for the execution of
utility and any child processes it spawns, as per
wait4(2).