sort in linux bash
your list of files in a paticluer folder :
cluster_data.txt
cluster_49.txt
cluster_39.txt
cluster_44.txt
ls -ltr cluster_*.txt | grep -v cluster_data.txt # will do the sort
OR
ls -ltr cluster_*.txt | grep -v cluster_data.txt | sort -t _ -k 2 -g
^ avoid this file
-t separator
-k key/column
-g general numeric sort
https://stackoverflow.com/questions/17061948/sorting-strings-with-numbers-in-bash