Bash: Append rows from multiple files to one output file and add file name as column

Question

This is a continuation of my previous question Bash: Choose row with the highest value in specified column in multiple files and create one output file with rows containing the max

The solution I used is:

for file in mi*
do
    sort -k14,14 -n $file | tail -1
done > result

I am wondering if there is an easy way to edit this code so that when I create the output file I can add a column that contains the file names, or if I need to use a different approach.

I found this question Bash Command Get Data from multiple files and append the file name but I am not sure how to adapt it for my needs

Update with more info: files are tsv and have column names

Answer 1

for file in mi*
do
    printf "%s " $file
    sort -k14,14 -n $file | tail -1
done > result

Or

for file in mi*
do
    echo "$file $(sort -k14,14 -n $file | tail -1)"
done > result

Depending on your delimiter you can replace the space after the filename with a different character.

Answer 2

The trick is to put what would have been sent to stdout into a variable and then output that variable and the filename.

You can change the order of the variables in the echo and also add a delimiter if that is significant.

eg.

for file in mi*
do
    myline=$(sort -k14,14 -n $file | tail -1)
    echo "$file $myline"
done > result

The answer you found uses a command named grep for searching; if searching multiple files, grep can optionally prepend the filename where the searched string was found.