The first thing needed is the ftp script:

#!/bin/bash
ftp -in ftp.hostname.com << SCRIPTEND
user [email protected] ftppassword
binary
cd /backups
mget filename.tar.bz2
SCRIPTEND
./alertmail

The next one is the email alert that is sent automatically when the task is over:

$cat alertmail
#!/bin/bash
echo "This is the server at joel.co.in. Your file has been downloaded!" | mail -s "FTP task done" "[email protected]"[

 

The next is a script that invokes nohup to prevent the task from terminating when the shell terminates:

cat dontcancel
#!/bin/bash
nohup $1

An ampersand may be inserted at the end to keep the process in the background.