That’s wizardry for you.   How many times have you typed grep ‘^$’?

Do you grep?

grep, the Unix command that searches files for patterns, is one of the most useful Unix utilities.   This example here grep ‘^$’ passes a regular expression with two characters:  a carrot (^) which means the beginning of line, and a dollar sign ($) which means, end of line.  Taken together they say, return me ever blank line – that is, has nothing between beginning and end of line.

Here it is in action.  Show me everything that is meaningful in my apache configuration file – that which is not a comment and is not a blank line.  The -e allows multiple patterns.  The -v of course reverses things, it shows everything not matching the pattern.

grep -ve '^#' -e '^$' apache2.conf | more