Task: Counts total number of only lines with alphanumeric symbols in all *.php files in the /testbed folder and subfolders.
Command: find /testbed -name '*.php' | xargs cat | awk '/[a-zA-Z0-9]/ {i++} END{print i}'
Equivalent command: find /testbed -type f -name '*.php' -exec grep -H '.*[[:alnum:]].*' {} + | wc -l