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
find /path/to/dir -newermt yyyy-mm-dd ! -newermt yyyy-mm-dd -ls

# create directory in all subdirectories
find -mindepth 1 -maxdepth 1 -type d -exec mkdir {}/en_US \;

# count files in a directory
find /path/to/dir -type f | wc -l

# find files from a user
find / -user foo

# find files with SUID bit
find / -perm 4000
find / -perm /u+s
find / -perm -u+s

# find print filename only
find /tmp -printf "%f\n"

# find big files
find /home -size +1G -ls

# find file with size between
find . -type f -size +8M -size -10M -ls

find . -type d -size +4096c

# Remove files older then 1 day from /tmp
find /tmp/ -mtime +1 -exec rm -r {} \;