UNIX / Linux Command To Check Existing Groups and Users

To check the existing groups and users on a Unix or Linux system, you can use the following commands:

1. groups: The groups command displays the names of the groups to which the current user belongs. For example:

$ groups

To display the groups of a specific user, you can use the groups command followed by the username. For example:

$ groups jane

2. id: The id command displays the user and group ID (UID and GID) of the current user, as well as the names of the groups to which the user belongs. For example:

$ id

To display the user and group information for a specific user, you can use the id command followed by the username. For example:

$ id jane

3. getent: The getent command displays information about entries in the system's databases, such as the user and group databases. You can use it to display the list of users and groups on the system.

To display the list of users, you can use the following command:

$ getent passwd

To display the list of groups, you can use the following command:

$ getent group

Note: These commands may have different options and syntax depending on your Unix or Linux distribution and version. Consult the groups, id, and getent man pages or documentation for your system for more information.