I need to set a daily backup of a specific external hard drive in iMac to a FTP server. In Windows I use a batch file but with OS X I'm a little lost.
You may write this script and it will work for not big number of files, but entire external hard drive backup to ftp server only using bash is a hard task. Because of possible connection problem, because of namespace problem. (Some file names on Mac ) may be impossible to store on your ftp server. If you backup small number of files ~100mb just zip them and upload with sh ftp command. But if the amount of data is large >1gb it is better to use third party software like "immortal files" or "goodsync".