List directories with most inodes at the top:
du -s --inodes * | sort -rn
Delete files older than 30 days ending with .txt from current directory
find . -type f -name "*.txt" -mtime +30 -exec rm {} \;
List the largest files of a directory sorted by large to small 10 max
find . -type f -exec du -h {} + | sort -rh | head -n 10
Find empty folders and delete
find . -type d -empty -exec rmdir {} \;
Find and remove files
find . -type f -name '*}.pdf' -exec rm {} +