find
# find files without read / write permissions for other
find /media/foo /media/bar ! -perm -o+rw -exec ls -l {} \;
find /media/foo /media/bar -ctime -1 -type f ! -perm -go+rw -exec chmod a+rw {} \;
find /media/foo /media/bar -1 -type d ! -perm -go+rwx -exec chmod 777 {} \;
# find all empty files
find /tmp -type f -empty
# find empty directories
find . -type d -empty
# print file content
find ./ -type f | while read f; do printf "\n# file %s\n" "$f"; cat "$f"; done
# find files by date
find /path/to/dir -newermt "yyyy-mm-dd"
# list all files modified on given date