TIME(1) | General Commands Manual | TIME(1) |
time
— time
command execution
time |
[-al ] [-h |
-p ] [-o
file] utility
[argument ...] |
The time
utility executes and times the
specified utility. After the
utility finishes, time
writes
to the standard error stream, (in seconds): the total time elapsed, the time
used to execute the utility process and the time
consumed by system overhead.
The following options are available:
-a
-o
flag is used, append to the specified
file rather than overwriting it. Otherwise, this option has no
effect.-h
-l
-o
file-a
flag
is not specified, the file will be overwritten.-p
time
output POSIX.2 compliant (each time is
printed on its own line).Some shells may provide a builtin time
command which is similar or identical to this utility. Consult the
builtin(1) manual page.
If time
receives a
SIGINFO
(see the status argument for
stty(1)) signal, the current time the
given command is running will be written to the standard output.
The PATH
environment variable is used to
locate the requested utility if the name contains no
‘/
’ characters.
If utility could be timed successfully, its
exit status is returned. If utility terminated
abnormally, a warning message is output to stderr. If the
utility was found but could not be run, the exit
status is 126. If no utility could be found at all,
the exit status is 127. If time
encounters any other
error, the exit status is between 1 and 125 included.
Time the execution of ls(1) on an empty directory:
$ /usr/bin/time ls 0.00 real 0.00 user 0.00 sys
Time the execution of the cp(1) command and store the result in the times.txt file. Then execute the command again to make a new copy and add the result to the same file:
$ /usr/bin/time -o times.txt cp FreeBSD-12.1-RELEASE-amd64-bootonly.iso copy1.iso $ /usr/bin/time -a -o times.txt cp FreeBSD-12.1-RELEASE-amd64-bootonly.iso copy2.iso
The times.txt file will contain the times of both commands:
$ cat times.txt 0.68 real 0.00 user 0.22 sys 0.67 real 0.00 user 0.21 sys
Time the sleep(1) command and show the results in a human friendly format. Show the contents of the rusage structure too:
$ /usr/bin/time -l -h -p sleep 5 real 5.01 user 0.00 sys 0.00 0 maximum resident set size 0 average shared memory size 0 average unshared data size 0 average unshared stack size 80 page reclaims 0 page faults 0 swaps 1 block input operations 0 block output operations 0 messages sent 0 messages received 0 signals received 3 voluntary context switches 0 involuntary context switches 2054316 instructions retired 2445544 cycles elapsed 241664 peak memory footprint
The time
utility is expected to conform to
ISO/IEC 9945-2:1993 (``POSIX'').
A time
utility appeared in
Version 3 AT&T UNIX.
January 15, 2021 | macOS 14.6 |