Linux Time Command with Examples

Linux Time Command with Examples
Linux Time Command with Examples

Linux Time Command

Time command in Linux is used to determine total execution time of the given command. Mainly used to check the performance of commands and scripts. Using Time command you can also compare total download time for a file using wget and curl commands. In this tutorial, you are going to learn Linux time Command with Examples.

Basic Syntax of Time Command

Following is the basic syntax for time command in Linux:

time [-p] command [arguments...]

-p: to print time summary in POSIX form this option is used.

Time Command Versions

Linux shells like Bash, Zsh both have their own version of time command which takes precedence over GNU time command. So to check whether you are using GNU time time command or not use the following command:

time

The output should be one of the following:

# GNU time (sh)
time is /usr/bin/time

# Bash
time is a shell keyword

# Zsh
time is a reserved word

If you didn’t get output like time is /usr/bin/time then you should use time command like given below. specifying the full path.

/usr/bin/time

Now check the type, you will get time is /usr/bin/time as output.

Time Command Examples

Following are the examples for time command.

Check time taken by the df command

To check time taken by df command to show free disk space run below command:

time df

The output should be:

Filesystem     1K-blocks    Used Available Use% Mounted on
udev             3941960       0   3941960   0% /dev
tmpfs             794444    1896    792548   1% /run
/dev/sda5       51343748 6024104  42681828  13% /
tmpfs            3972204  111068   3861136   3% /dev/shm
tmpfs               5120       4      5116   1% /run/lock
tmpfs            3972204       0   3972204   0% /sys/fs/cgroup
/dev/sda6       82045336 2879060  74955588   4% /home
/dev/sda2          98304   30413     67891  31% /boot/efi
tmpfs             794440      16    794424   1% /run/user/120
tmpfs             794440      32    794408   1% /run/user/1000

real	0m0.004s
user	0m0.003s
sys	0m0.001s

Check time taken by the wget command

To check the execution time for wget command for downloading Google Chrome setup file run below command:

time wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb

The last portion of output should look like:

2019-02-26 23:21:35 (878 KB/s) - ‘google-chrome-stable_current_amd64.deb’ saved [57089254/57089254]

[1]+  Done                    time wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb?src=0

real	1m4.812s
user	0m1.627s
sys	0m4.346s

 

Where,
real: The time from start to finish. (starts when ENTER is pressed)
user: The total amount of CPU time used in User Mode.
sys: The total amount of CPU time used in Kernel Mode.

Conclusion

You have successfully learned Linux time command with examples. If you have any queries please don’t forget to comment below.

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