useless emits an augmented copy of a UNIX group file, with the configured group's entry modified to append the desired username. This shim is useful for automatically updating groups in environments where a system's usermod command omits the typical -a, -G flags to perform this operation.
For manual group changes, nano, cat, echo, etc. can safely edit the /etc/group file. However, this requires some care to avoid accidentally corrupting the file. This shim provides a more reliable, automated workflow, intended for system administrators, Continuous Integration servers, virtual machine configuration, and so on.
$ sudo cp /etc/group /etc/group.bak
$ USERNAME=beer GROUP=party su user -c 'awk -f lib/useless.awk < /etc/group > /etc/group.new'
$ diff /etc/group /etc/group.new
3c3
< party:x:101:sshd,user
---
> party:x:101:sshd,user,beer
$ sudo cp /etc/group.new /etc/group- GNU awk
- diff