This command will create an encrypted image on mac OS X that will grow as you need it.
Since I could not find anywhere on the net, I dig on the hdiutil man page and wrapped the command.
The image starts with about 600MB in size, which is not wasted actually.
I use this image to backup my sensitive data such as servers config files, mysql databases and repositories.
I set it to use AES 128bit encryption.
Case-sensitive, because Linux fs are Case-sensitive by default. If you don’t set it Case-sensitive you cannot use for linux backups.
hdiutil create -encryption AES-128 -stdinpass -fs “Case-sensitive HFS+” -type SPARSE -nospotlight -volname Servers Servers
it will create a file named Servers.sparseimage

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