SHELL

linux show groups

cut -d: -f1 /etc/group | sort

linux show groups

cat /etc/group

cat /etc/groups | grep <groupname>
  
# Example:
cat /etc/groups | grep sudo
# Output
sudo:x:27:<user1>, <user2>, <user3>...

# sudo : group name
# x : password (encrypted for security reasons)
# 27 : could be another number, represents group ID
# list of users in group

linux groups

cut -d: -f1 /etc/group | sort