How to list group members and show user id and full name
 

After finding this to show all users on a system I was wondering what modification would work to just show members of a given group, show their user id and full name?

awk -F":" '{ print "UserName: " $1 "\tUserID:" $3 "\tFullName: " $5 }' /etc/passwd

/etc/passwd contains the primary group of the user (the one specified with -g in useradd). If, however, the user is a member of secondary groups (specified with -G in useradd/usermod) then your script wouldn't find them. You'd need to add info to get info from /etc/group as well.

So your command would need to be modified to print the group field "$4" rather than the user field "$3" for primary:
awk -F":" '{ print "UserName: " $1 "\tUserID:" $4 "\tFullName: " $5 }' /etc/passwd

However as noted that wouldn't get secondary groups. You'd have to script that. The command "groups <username> will show you in which group names the specified user is a member. Also the "id <username>" will show you in which group numbers the specified user is a member.

You'd have to make a modified script that got user's from /etc/passwd then got the group information for them using your choice of groups or id.