On-the-fly backup (backup a running system)
sudo rsync -e "ssh -i ${HOME}/.ssh/id_rsa" -av --delete --numeric-ids --exclude=proc/* --exclude=sys/* --exclude=tmp/* root@${HOST}:/ .

limit bandwith to 2 mbit/s
rsync --bwlimit=2000 --delete -avz /media/backup/$(date -I)/

# Specify SSH key and configuration
sudo rsync -av \
-e "ssh -i /home/foo/.ssh/id_rsa -F /home/foo/.ssh/config" \
--delete \
--numeric-ids \
-av \
/from/dir/ root@



# 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