Meaning of root:wheel

Question

What does root:wheel mean in the following?

chown root:wheel myfile

Solution 1

root is a user (the super user) and wheel is a group (of super users I guess).

chown root:wheel myfile

means making myfile belong to the user root and the group wheel (read man chown for more information).

Solution 2

More specifically about the wheel group:It is a Unix group specifically intended for only those users who have rights to su as root.

Comments

[Michael Mrozek]

wheel is typically the group with sudo rights (see this question)

[vk5tu]

Some Unixen do this for files which are to be accessed by system administrators. Typically these file will have a user:group of root:wheel and permissions rw-rw----. This approach has fallen out of favour, as it allows system changes to be too readily made in error (eg, cd /etc; …; vi hostname would succeed); rather the modern approach has system files owned by root:root and requires the use of the sudo command prior to successfully changing a file (eg, cd /etc; …; vi hostname would fail, only the more intentional sudo vi hostname succeeds).