Find all files with the extension ".txt" in the current directory, search for the string "ABC" in each of those files, print the second column of the output, sort the output, count the number of occurrences of each unique value, and sort the output by number of occurrences in descending order.
`find . -name "*.txt" | xargs grep 'ABC' | awk '{print $2}' | sort | uniq -c | sort -nr`