This is an old revision of the document!

Helpful Ubuntu/Linux Commands and Procedures

List hard drive serial numbers

lsblk --nodeps -o name,serial

List processes and the ports they are listening on

netstat -tulpn | grep LISTEN

Reload systemd manager configuration after changes made

sudo systemctl daemon-reload

List all installed packages

apt list --installed

Search for available packages

apt-cache search <keyword>

Changing default editor for visudo

sudo update-alternatives --config editor

Disable GUI screen lock

Settings -> Privacy -> Screen Lock

Disable GUI screen blanking

Settings -> Power -> Blank Screen

Create Samba User

sudo smbpasswd -a <username>

List Samba Users

sudo pdbedit -L

Determine the date the system was installed (not 100% reliable)

tune2fs -l /dev/vda2 | grep ‘Filesystem created:’ (replace vda2 with device where root filesystem is located)

Finding largest files/directories

du -a /dir/ | sort -n -r | head -n 20 (replace 20 with the # of lines you wish to have returned)

Disable colors in the vi editor by default

Create (or edit, if it exists) ~/.vimrc; into this file add the command syntax off, and save the file.

Overwrite/blast the boot block on the hard drive (ONLY when you want to re-install the operating system!)

dd if=/dev/zero of=/dev/sda count=1 bs=512

Find files consuming the root file system

mkdir /tmp/rootbind
mount --bind / /tmp/rootbind
du -d 1 -h /tmp/rootbind

Solution for Linux systems not visible in the "Network Neighborhood" on Windows machines

apachectl install wsdd

View video resolution capabilities

xrandr -q

Cookbook for passing client IP address to systems behind a reverse proxy

On the reverse proxy:

Ensure that websockets support is enabled

On the host:

Create /etc/apache2/conf-available/remoteip.conf with the following contents:

RemoteIPHeader X-Forwarded-For
RemoteIPTrustedProxy x.x.x.x (replace w/ IP address of trusted proxy)

Execute the commands:

ln /etc/apache2/conf-available/remoteip.conf /etc/apache2/conf-enabled/remoteip.conf
ln /etc/apache2/mods-available/remoteip.load /etc/apache2/mods-enabled/remoteip.load

Edit /etc/apache2/apache2.conf and find the LogFormat lines. Change each occurrence of %h to %a.

Restart apache.