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

apt install wsdd

View video resolution capabilities

xrandr -q

Converting OTA DVR recordings to .MP4

OTA DVR recordings are saved as .ts files, which are not compatible with DaVinci Resolve (my video editor of choice). For this reason, we must convert the files into a format that “DR” can comprehend. We can do this on linux using the ffmpeg package:

ffmpeg -i <inputfile.ts> -vcodec copy -acodec copy <outputfile.mp4>

Generate password hashes (useful for Ansible playbooks amongst other things)

mkpasswd --method=sha-512

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.