如何删除以相同字符开头的行？

Question

I'm trying to clean up the output from someone else's script by removing the headers that have no content.

Output currently looks like this:

====== Header1 ======
====== Header2 ======
====== Header3 ======
information

I'm trying to remove the lines for Header1 and Header2, but not Header3. I found an awk command that removes all duplicate lines but the last that begin with the same character, so that helps for this issue, but causes a new problem when the 'information' bit is numerous lines that also begin with the same character (usually tabs).

Desired output post cleanup:

====== Header3 ======
information

Thanks

Answer 1

This awk might work for you:

$ awk '/^===/{h=$0;p=0;next}!p{print h};{p=1}1' file
====== Header3 ======
information

Or as Glenn pointed out, this also works:

awk '/^===/{h=$0;next}h{print h;h=0}1' file