Can Group ID (GID) be alpha characters rather than numerical values? Sorry for the total noob question, but I can't seem to find a straight answer online. I'd like to know if GID must be numerical values, or it can be alpha characters. In other words, is it customary to use, say, Marketing instead of 3000 for GID? Which way is used in a real setting? Thanks for your time!

The group identifier is always a number.

Technically, in specification terms, group identifiers have their own type, `gid_t`; but POSIX requires that -1 be a valid `gid_t`, which effectively means it has to represent numbers. (Historically, before `gid_t`, group identifiers were always numbers, so this couldn’t easily be changed anyway.)

In Linux, the `group` manual page specifies that the group identifier is a number.

In many contexts you _can_ use a group’s name, but ultimately what matters is the identifier. It’s also possible for multiple group names to share the same identifier (the mapping isn’t bijective).