I want the date and time to be added in a text file whenever I open it

Question

I was using windows 7,8.1, and 10 previously and there was an option in the Notepad that if I type .LOG at the beginning of the file (which is done only once), every time I open the notepad the date and current time will be automatically added.

Basically, I keep track of all my expenses and it's very important for me to just open the text file and it automatically adds the date and time for me. How can I do this in Ubuntu 15.04?

Answer 1

Simple.

#!/bin/bash
filetoedit="$1"
if [ "$(head -n 1 $filetoedit)" = ".LOG" ] ; then
    date >>$filetoedit
fi
vim "$filetoedit"

Put the above script in a file in your $PATH, make it executable and call your editor through it i.e. if you save it as open.sh, then open any file e.g. foo.txt for editing as :

open.sh foo.txt  

You can adjust the date format (see man date), and change the editor used by replacing vim with your choice.

See "Where should I put my script so that I can run it by a direct command?"