Primary Vs. Supplementary
In Unix systems, every user must be a member of at least one group, which is identified by the numeric GID of the user's entry in /etc/passwd. This group is referred to as the primary group ID. A user may be listed as member of additional groups in the relevant entries in the /etc/group; the IDs of these groups are referred to as supplementary group IDs.
Read more about this topic: Group Identifier
Famous quotes containing the word primary:
“A fact is a proposition of which the verification by an appeal to the primary sources of our knowledge or to experience is direct and simple. A theory, on the other hand, if true, has all the characteristics of a fact except that its verification is possible only by indirect, remote, and difficult means.”
—Chauncey Wright (1830–1875)