How to detect file ends in newline?

Question

Over at Can you modify text files when committing to subversion? Grant suggested that I block commits instead.

However I don't know how to check a file ends with a newline. How can you detect that the file ends with a newline?

Answer 1

@Konrad: tail does not return an empty line. I made a file that has some text that doesn't end in newline and a file that does. Here is the output from tail:

$ cat test_no_newline.txt this file doesn't end in newline$   $ cat test_with_newline.txt this file ends in newline $ 

Though I found that tail has get last byte option. So I modified your script to:

#!/bin/sh c=`tail -c 1 $1` if [ "$c" != "" ]; then     echo "no newline" fi 

Answer 2

Here is a useful bash function:

function file_ends_with_newline() {     [[ $(tail -c1 "$1" | wc -l) -gt 0 ]] } 

You can use it like:

if ! file_ends_with_newline myfile.txt then     echo "" >> myfile.txt fi # continue with other stuff that assumes myfile.txt ends with a newline