Hello,

Below, I have a unix command, which can be executable for single file.

cat input.txt | sort -k3,3 > output.txt

Why use cat ?
Doesnt sort -k3,3 input.txt > output.txt work?

For your directory you will need to use a loop and since your output is in another directory you can keep the same name as the one used as variable in the loop...

for FILE in ...
do
   sort -k3,3 $FILE >~newdirectory/$FILE
.
.
done

Similarly as it turned out:

ls -1d * | while read filename
do
       if [ -f "${filename}" ]
       then
            sort -k3,3 "${filename}" > "/your_path/your_directory/${filename}"
       fi
done