remove all lines from a text file starting at first empty line

Question

What is the best way to remove all lines from a text file starting at first empty line in Bash? External tools (awk, sed...) can be used!

Example

1:          


        

Answer 1

With AWK:

$ awk '/^$/{exit} 1' test.txt > output.txt

Contents of output.txt

$ cat output.txt 
ABC
DEF

Walkthrough: For lines that matches ^$ (start-of-line, end-of-line), exit (the whole script). For all lines, print the whole line -- of course, we won't get to this part after a line has made us exit.