sudo mount /dev/xxxx -o remount-ro /mnt
mkdir /backup; cd /backup
tar --exclude='./backup' --exclude='./mnt/backup' -cvjpf mybackup.tar.bz2 /mnt

Then you unpack with behavior permission

sudo tar -xvjpf mybackup.tar.bz2

Creating A Backup All Datebases And Restore

mysqldump -u root -p --all-databases > all_databases.sql
mysqldump -u root -p --all-databases < all_databases.sql

Creating A Backup Single Datebase And Restore

mysqldump -u root -p db_name > db_file.sql
mysqldump -u root -p db_name < db_file.sql

Split larger files into smaller parts? No problem!

Lets says I have an image and its too big (10MB). All I do is:

split --bytes=1M /path/to/image/image.jpg /path/to/image/prefixForNewImagePieces

and then to put it together I use cat:

cat prefixFiles* > newimage.jpg