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.

Solution 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.

Solution 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

Comments

[bahamat]

Perhaps you don't feel you need a partition table, but is there any reason why you should not have a partition table?

[William Nyqvister]

More things that can go wrong. Note my question is really a shell question, not a partition table question.

[bahamat]

You're claim that "more things can go wrong" is completely baseless. It sounds like you're using your fear and misunderstanding to fuel your bad decisions.

[William Nyqvister]

Look, bahamat, I'm just talking about myself. I know that if I have to do two things instead of one, my likelihood of screwing up goes up. Maybe it's different for you, but none of this is the subject of this question at all anyway. #troll

[William Nyqvister]

What does expect do differently than reading from stdin?

[Matthias Braun]

Why wouldn't it make sense, according to the man page, to create a file system on the unpartitioned device?

[mekb]

if there's another warning it won't send y