GNU Time

The `time' command runs another program, then displays information about the resources used by that program.

# measure time and resources used by 'make' to build a project
$ time make
[... make's output ...]
0.62user 0.09system 0:01.13elapsed 63%CPU (0avgtext+0avgdata 51888maxresident)k
57704inputs+712outputs (191major+24400minor)pagefaults 0swaps

# measure execution time and print in POSIX-compatible format
$ time -p make
[... make's output ...]
real 0.67
user 0.57
sys 0.08

# print measurements in custom format
[... make's output ...]
$ env time --format="Command '%C' ran for '%E' (%e seconds)" make
Command 'make' ran for '1:04.00' (64.00 seconds)

Often your shell (e.g. bash, zsh) will have its own built-in version of 'time' which takes precedence over GNU time. Use 'type' to determine whether time is a built-in keyword or not. Use 'env' or absolute path to force using the 'time' binary.

$ type time
time is a shell keyword   # bash's built-in time

% type time
time is a reserved word   # zsh's built-in time

$ type time
time is /usr/bin/time     # GNU time will be used

# The following methods bypass the built-in 'time' and use GNU time:
$ env time make
$ /usr/bin/time make
$ \time make

Getting Help


Stable source releases can be found at (local mirrors)

Latest Source

The latest source with revision history can be browsed using cgit, gitweb or Assuming you have git installed, you can retrieve the latest version with this command: git clone git://
Please note that we do not suggest using test versions of time for production use.

Mailing Lists

The main discussion list for all things related to GNU time is <>. If you have questions, comments, or other general discussion about time then this is the mailing list for that discussion. If you don't know where to start then this is the place to start. You can browse and search past postings to the bug-time archive.

A very useful and often referenced guide on how to write bug reports and ask good questions is the document How To Ask Questions The Smart Way .

You do not need to be subscribed in order to post messages to any GNU mailing list. However non-subscribers are moderated by humans so please be patient when waiting for your email to arrive.

You can subscribe to any GNU mailing list via the web as described below. Or you can send an empty mail with a Subject: header line of just "subscribe" to the relevant -request list. For example, to subscribe yourself to the main bug-time list, you would send mail to with no body and a Subject: header line of just "subscribe".

It has been necessary to moderate the time mailing lists to prevent the flood of spam. Postings to the lists are held for release by the list moderator. Sometimes the moderators are unavailable for brief periods of time. Please be patient when posting. If you don't eventually see the message in the list archive then it did not get posted.

Mailing List Etiquette

Please do not send messages encoded as HTML nor encoded as base64 MIME nor included as multiple formats. Please send messages as plain text. Please include a descriptive subject line. If all of the subjects are bug then it is impossible to differentiate them. Please avoid sending large messages, such as log files, system call trace output, and other content resulting in messages over about 40 kB, to the mailing lists without prior contact. Those are best sent directly to those requesting that information after initial contact.


Important announcements about GNU time and most other GNU Software are also made on mailing list .

Enhancement Requests

If you would like any new feature to be included in future versions of time, please send a request to <>. This is the general discussion list and a good place to start discussion of a new feature. If you would like to implement yourself, then note that non trivial changes require copyright assignment to the FSF as detailed in the "Copyright Assignment" section of GNU coreutils HACKING notes.

Please remember that development of GNU time is a volunteer effort, and you can also contribute to its development. For information about contributing to the GNU Project, please read How to help GNU.


GNU Time is currently being maintained by Assaf Gordon