Which is a common usermod command line option?

The command line option -aG is a commonly used option with the usermod command in Linux, which is used to modify user accounts. Specifically, -aG allows an administrator to add a user to one or more supplementary groups without removing them from other groups they are already a member of. This is particularly important in managing user permissions and access to resources in a multi-user environment.

When using usermod -aG groupname username, the specified user will be added to the group while retaining their membership in any existing groups. This functionality is crucial for ensuring that users have the appropriate permissions as they are assigned to new roles or responsibilities without losing previous access rights.

The other options presented, like -add, -create, and -remove, are not valid options in the context of the usermod command syntax. In fact, there are no standalone -add or -create options for user modification, as usermod focuses on modifying existing user attributes rather than creating new users or adding them without the appropriate syntax. The -remove option is also not correct as it does not function in conjunction with usermod in