1 wall "Hello, world!" will send a message that looks like 1 2 3 Broadcast message from root@localhost (pts/0) (Sat Feb 1 14:50:14 2024): Hello world! to every user currently logged in to the system. When might this be relevant? When you’re working in a small team, by remoting into custom hardware, and constantly reflashing the device, to give everyone a heads up, for instance: ...
1 2 # ⚠️: Reboots your VM. su -c "$(whereis adduser | awk '{print $2}') $(whoami) sudo && $(whereis reboot | awk '{print $2}')" In all its glory! For Debian 10 and up, because Debian 10 is where the sysv to systemd conversion became totalizing. Let’s break down quickly why each part of this is needed: Since we are trying to add ourselves to the sudo group right now, we obviously can’t use sudo. Enter su -c to switch to root, run a command, and then switch back out. whereis adduser instead of simply adduser because adduser is no longer in the $PATH by default anymore. Tempted to try which adduser? No dice – which only gets you things in the $PATH as well: 1 2 3 andrew@debian-10:~$ which adduser # zip, zilch, nada. andrew@debian-10:~$ whereis adduser adduser: /usr/sbin/adduser /etc/adduser.conf /usr/share/adduser /usr/share/man/man8/adduser.8.gz awk to rip out /usr/sbin/adduser, which - thankfully - at least is still executable. $(whoami) because your name might not be andrew! whereis reboot because I don’t want to have to manually remember to logout and login again.