Change group ID of a set of users...

[Leandro Sales]

... How can I do that?

Leandro.

[Sivaram N]

usermod -g should do it. 'man usermod' should explain it all.

[Mark Fenton]

or to wrap that in a little loop ---

export USERS="list of the users you want"
for USER in USERS
do
usermod -g $USER
done

[Mark Fenton]

oops, left out the '$' in front of $USERS

(sorry)