Notes from this years Australian Linux Conference (amusingly being held in Dunedin, New Zealand). This isn't intended to be comprehensive in any way, just a list of the things that I thought were interesting.
Inside a Debian Package
fakeroot is cool. runs a shell/script and lies to everything inside of it telling things that they are root and are allowed to change permissions on files. it also caches any changes to the filesystem (instead of making them) and then reports the changes back to anything else that asks. debian uses this to build tar packages which hold root/suid files inside them without having to run the actual build scripts as root.
ronin(adam)$ id
uid=999(adam) gid=100(users) groups=100(users),0(root),33(www-data),38(list),111(fuse)
ronin(adam)$ fakeroot bash
ronin(root)# id
uid=0(root) gid=0(root) groups=100(users),0(root),33(www-data),38(list),111(fuse)
ronin(root)# touch /etc/shadow
touch: cannot touch `/etc/shadow': Permission denied
ronin(root)# ls -l /etc/shadow; chown adam /etc/shadow; ls -l /etc/shadow
-rw-r----- 1 root root 2371 Jan 6 15:58 /etc/shadow
-rw-r----- 1 adam root 2371 Jan 6 15:58 /etc/shadow
ronin(root)# exit
ronin(adam)$ ls -l /etc/shadow
-rw-r----- 1 root shadow 2371 Jan 6 15:58 /etc/shadow
A Few Useful Tools
- netmask - will tell you what the "normal" netmask is for any gibberish you get given. will generate tradition, cidr or cisco style netmasks.
- munin - nice client/server based statistics monitoring package.
- iptraf - nice curses based networks monitor.
- i didn't know you could chain -exec's in find, eg: find . -type f -exec grep {} \; -exec echo {} \;