A change in structure might be helpful: $ ls data 0001.csv 0002.csv 0003.csv 0004.csv ... $ ls algorithm_a 0001.csv 0002.csv 0004.csv ... $

A change in structure might be helpful: $ ls data 0001.csv 0002.csv 0003.csv 0004.csv ... $ ls algorithm_a 0001.csv 0002.csv 0004.csv ... $ diff -q algorithm_a data |grep ^Only |sed 's/.*: //g' 0003.csv ...