使文件夹中的所有文件与最长的文件一样长

Question

I've got many .txt files that contain many lines with a single column of data. However, the length of the files are not the same. Some files have 2000 lines, others 2001 lines etc.

Sometimes there's a single blank line at the end which I want to remove.

I want to append lines of 0 to the end of all but the longest file, so that the line numbers of all files are equal.

I would like this to be solved with a simple shell script.

Answer 1

First you have to find the file with the most lines. After that, you can append lines to the other files until they have as many lines as the file with the most lines.

Here we append lines containing the text 0 until the file has as many lines as the file with the most lines.

To remove a blank line at the ending first, you can use sed :

sed -i '${/^$/d}' /home/kisa/data/*.txt
max=$(wc -l /home/kisa/data/*.txt | head -n-1 | sort -n | awk 'END {print $1}')
for f in /home/kisa/data/*.txt; do
  n=$(wc -l < "$f")
  yes 0 | head -n $((max-n)) >> "$f"
done