Find all files with the extension ".log" and execute a grep search for the string "Error" in each file. Then, print the second column of the output, sort the output, count the number of occurrences of each unique value, and sort the output in reverse numerical order.
find . -name "*.log" -exec grep '^Error' {} \; | awk '{print $2}' | sort | uniq -c | sort -rn