How do I script mkfs asking "is entire device, not just one partition! Proceed anyway?"

Question

I'm trying to create a script that formats an Amazon EC2 EBS volume, so I can mount it.

From the command-line, it looks like this:

> mkfs -q -t ext4 /dev/sdf
/dev/sdf is entire device, not just one partition!
Proceed anyway? (y,n) 

(The command is correct; no need to create a partition table for my purpose)

My problem: because this command is supposed to be run in an automated script, I can't have that question on the terminal; nobody will be answering and the script will hang. How do I avoid this?

I tried:

> echo y | mkfs -q -t ext4 /dev/sdf

but that doesn't do the trick. The -q option makes no difference either.

Answer 1

From the manpage:

   -F     Force mke2fs to create a filesystem, even if the specified device is not a partition on a block special device, or  if  other
          parameters do not make sense.

So call mkfs.ext4 directly instead of via mkfs, and add the -F parameter to ignore this warning.

Answer 2

expect is what you're looking for. Try something like this:

#!/usr/bin/expect

spawn mkfs -q -t ext4 /dev/sdf
expect "/dev/sdf is entire device, not just one partition!\nProceed anyway? (y,n)"
send -- "y\r"

expect eof