Time command's illegal option

Question

I am having some issues with the time command time. It works fine but since time gives 3 numbers in output(real, user and sys) I was looking on how to get only the user time. I found many posts that say to use /usr/bin/time -f "%U" but I get this errors :

/usr/bin/time: illegal option -- f
usage: time [-lp] command.

I also can't find the option -f when I type man time

I tried to skip it and write:/usr/bin/time "%U" and I get %U: No such file or directory

I have installed GNU-time but nothing changed. what is the issue?

Possible duplicate of [Gnu time and formatting output](https://stackoverflow.com/questions/9715570/gnu-time-and-formatting-output) — Daniel W., Apr 04 '19 at 09:45
[The `-f` option is totally fine](https://www.gnu.org/software/time/), you are accessing the wrong binary. The `time` you installed, must be somewhere else located on your computer. Click the link, it shows how to find out which `time` you are using (`type time`). — Daniel W., Apr 04 '19 at 10:00
then why does `man time` only shows `-l` or `-p` as options? — basel117, Apr 04 '19 at 10:05
If you installed `gnu-time` with **homebrew**, you need to use `gtime` or `/usr/local/bin/gtime` if you didn't set your PATH. — Mark Setchell, Apr 04 '19 at 10:07
Wow, nice information Mark, this `g` prefix is new to me, too. I have added `gnu` and `macos` tags to the question. The situation is different on generic linux systems. — Daniel W., Apr 04 '19 at 11:23

Mark Setchell · Accepted Answer · 2019-04-04T10:18:16.037

There are several time commands...

If you run:

type time

and get:

time is a shell keyword

that means you are using bash's built-in shell command that does not accept the option you want. The help for this command, like all shell built-ins, is available using:

help time

If you run:

type time

and get:

time is hashed (/usr/bin/time)

that means you are using the Apple-supplied (BSD-like) time command that does not accept the option you want. That is also the one described in the man-pages.

If you installed gnu-time with homebrew, you need to run:

gtime

unless you didn't set your PATH to include /usr/local/bin like you should if you use homebrew, in which case you would need to run:

/usr/local/bin/gtime

and view the man-page with:

man gtime

If you want to always use the command time in place of gtime, and I would not recommend this, you need to run:

brew info gnu-time

and read what it says about setting:

PATH="/usr/local/opt/gnu-time/libexec/gnubin:$PATH"

Time command's illegal option

1 Answers1