To Convert a Load of Document Files into Plain Text (In Order to Diff Them)

for i in * ; 
do 
  echo "$i" ;
  libreoffice --headless --convert-to txt:Text "$i" ; 
done

To Play a Random Sound File in a Tree

mplayer "$(find . -name "*.3gp" | shuf -n1)"

To type Latin Macrons āēīōū

in X generally, you need to use the Compose key, most keyboards don't have one, so Compose is usually done with shift+Alt Gr,

Compose - a and Compose a - will both produce an ā

but it's more convenient to make the right Alt key (AltGr) be the compose key

to try it in a terminal
setxkbmap -option "compose:ralt"

to make it the system default:
sudo dpkg-reconfigure keyboard-configuration

you can also get it to work just in your desktop environment with e.g. in xfce, Applications/Settings/Keyboard/Layout

To play all the sound files in a tree

find . -name "*.3gp" -exec mplayer {} \;

To Turn .midi Files Into .wav Files

for i in *.midi; do timidity -Ow -o  "${i%.midi}.wav" "$i" ; done

To Play a Random Video

mplayer -fs "$(ls | shuf -n1)"

To move the five most recent files to a subdirectory

ls -rt will show you the files most recent first.

To move the most recent five to a subdirectory:

mkdir -p recent && find -maxdepth 1 -type f -printf '%T@ %P\n' | sort -rn | cut -d' ' -f2- | head -n 5 | xargs -I{} mv {} recent

To Find the Most Recent Version of a File

Occasionally it so happens that you want to find the most recent version of thing.

Suppose that you're trying to find your most recent timesheet.

Then:

find ~ -type f -name "*timesheet*" -printf "%T@ %t %p\n" | sort -n 

does the business.

Output looks something like:

1519655146.5096155360 Mon Feb 26 14:25:46.5096155360 2018 /home/john/data/.~/timesheet.py.~86~
1519925511.1565392570 Thu Mar  1 17:31:51.1565392570 2018 /home/john/data/.~/timesheet.py.~87~
1520000595.5182763930 Fri Mar  2 14:23:15.5182763930 2018 /home/john/data/timesheet.py

Where the first column is a sortable version of the last modification time "%T@", and the second "%t" is the human readable form.

The last thing printed will be the most recent file in your home directory tree with timesheet in the name.

Linux Laptop Battery Level

sudo apt-get install acpi 
acpi -V

or:

upower -i `upower -e | grep 'BAT'`