[SOLVED] Can I use the sed command to replace multiple empty line with one empty line?

Issue

I know there is a similar question in SO How can I replace mutliple empty lines with a single empty line in bash?. But my question is can this be implemented by just using the sed command?

Thanks

Solution

Give this a try:

sed '/^$/N;/^\n$/D' inputfile

Explanation:

• /^$/N - match an empty line and append it to pattern space.
• ; - command delimiter, allows multiple commands on one line, can be used instead of separating commands into multiple -e clauses for versions of sed that support it.
• /^\n$/D - if the pattern space contains only a newline in addition to the one at the end of the pattern space, in other words a sequence of more than one newline, then delete the first newline (more generally, the beginning of pattern space up to and including the first included newline)

Answered By - Dennis Williamson

Answer Checked By - Timothy Miller (WPSolving Admin)