Команда newgrp
Log into a new group.
newgrp [ -| -l ] [ group ] [argument]
| - | -l | Change the environment to what would be expected if the user actually logged in again as a member of the new group. |
| group | A group name from the group database or a non negative numeric group ID. Specifies the group ID to which the real and effective group IDs will be set. If group is a non-negative numeric string and exists in the group database as a group name, the numeric group ID associated with that group name will be used as the group ID. |
| argument | sh and ksh only. Options and/or operand of the newgrp command. |
newgrp - return you to a prompt of a new shell.