The ac command is a Unix utility that is used to display statistics about users' connect time. It displays the total connect time for all users or for a specific user. The connect time is the amount of time that a user has spent logged into the system.
The ac command is typically used by system administrators to monitor user activity and to track the amount of time that users spend logged into the system.
Note that the accounting file wtmp is maintained by init(8) and login(1) but neither ac nor login actually creates the file. If wtmp doesn’t exist, then no report is generated, but you can point ac to an alternate location using the --file option. If a wtmp file doesn’t exist on your system, you can create an empty wtmp file to enable reporting on your system.
Since the ac command is based on UNIX, to use it on Linux, you need to install it.
Installing the ac Command in Linux
The ac command is not installed by default on most Linux systems, so you will need to install it manually.
To do this, you will need to use the package manager for your particular Linux distribution. For example, on Ubuntu or Debian, you can use the apt-get command to install the ac package as follows
sudo apt-get update
sudo apt-get install ac
If you get the error: E: Unable to locate package ac, it is likely that the package is not included in the default repositories for your version of Debian or Ubuntu. In this case, you will need to add a repository that contains the ac package to your system's list of repositories.
To do this, you will need to edit the /etc/apt/sources.list file to add a repository that contains the ac package. For example, if you are using Debian 10 (Buster), you can add the following line to your sources.list file:
deb http://deb.debian.org/debian buster main
This will add the main repository for Debian 10 (Buster) to your system's list of repositories. Once you have added this repository, you can update your system's package list and install the ac package with the following commands:
sudo apt-get update
sudo apt-get install ac
On CentOS or Red Hat, you can use the yum command to install the ac package:
sudo yum update
sudo yum install ac
Using the ac Command
Once the ac package is installed, you can use the ac command to display connect time statistics for users on your system. For example, to display the total connect time for all users, you can run the following command:
ac -d
To display the connect time for a specific user, you can run the ac command with the -p option followed by the username:
ac -p username
You can also use the -s option to specify a start date and the -e option to specify an end date to limit the connect time statistics to a specific time period.
For more information about the ac command and its options, you can run the man ac command to view the manual page for the ac command.