I’m able to use sed /^$/d <file> to delete all the blank lines in the file, but what if I want to print all the blank lines only? The command sed /^$/p <file> prints all the lines in file.
The reason I want to do this is that we use an EDA program (Expedition) that uses regex to run rules on the names of nets. I’m trying to find a way to search for all nets that don’t have names assigned. I thought using ^$ would work, but it just ends up finding all nets, which is what /^$/p is doing too. So is there a different way to do this?
Unless otherwise specified sed will print the pattern space when it has finished processing it. If you look carefully at your output you’ll notice that you get 2 blank lines for every one in the file. You’ll have to use the -n command line switch to stop sed from printing.
Should work as you want.