Which option should be used with the groupadd command to create a system group?

To create a system group using the groupadd command, the -r option is used. When this option is specified, it instructs the system to create a group with a GID (Group Identifier) that is within the range typically reserved for system groups. System groups are generally those groups with GIDs from 0 to 999 (or depending on the system configuration, possibly up to 1999), which are distinguished from regular user groups that usually have higher GIDs starting from 1000.

This is particularly important for managing user permissions and ensuring that groups associated with system-level processes and services operate under the correct privileges. By using the -r option, you ensure that the created group is treated as a system group, which can help in organizing and managing permissions for services that require these specific group configurations.

The other options serve different purposes. For instance, the -g option is used to specify a particular GID for the new group, rather than creating it as a system group. The -s option does not apply in the context of group creation since it pertains to shell assignment for users. Lastly, -t is not a valid option with the groupadd command. Understanding the distinction of these options is critical for effective user and