How to delete blank lines?

To delete blank lines from a file in Bash, you can use the sed command. Here’s how to do it:

Using sed

To delete all blank lines from a file named file.txt, use:

sed -i '/^$/d' file.txt

Explanation:

• sed: Stream editor for filtering and transforming text.
• -i: Edits the file in place.
• /^$/: A regular expression that matches empty lines (lines with no characters).
• d: Command to delete the matched lines.

Alternative Using grep

You can also use grep to achieve the same result:

grep -v '^$' file.txt > temp.txt && mv temp.txt file.txt

Explanation:

• grep -v '^$': This command outputs all lines that do not match the empty line pattern.
• > temp.txt: Redirects the output to a temporary file.
• mv temp.txt file.txt: Replaces the original file with the modified one.

Feel free to ask if you have more questions or need further clarification!