The Elite List

Create bootable USB using 'dd' command.

Solution
sudo dd bs=4M if=path/to/input.iso of=/dev/sd conv=fdatasync status=progress

Replace input file path and drive letter(sda/b/c). Use 'lsblk' if confused. Source - https://askubuntu.com/a/377561

Solution
echo 'input' >> filename

Attachs the input to the file. Source - https://www.cyberciti.biz/faq/linux-append-text-to-end-of-file/

Solution
tail -c 100 filename

Prints last 100 bytes of the file. Source - https://unix.stackexchange.com/a/167816

Solution
sed -i '1s/^/abcde /' filename

Attachs the input to the file beginning. Source - https://stackoverflow.com/a/9533736/6903724

Solution
sudo dpkg -i /path/a.deb

Use 'sudo apt install -f' for any missing dependencies. Source - https://unix.stackexchange.com/a/159114

Solution
head -c 100 filename

Prints first 100 bytes of the file. Source - https://unix.stackexchange.com/a/167816