Bash update cdrom status

[Johnny Rosenberg]

Let's say I have a cd-r/w in my cd burner. It's not empty:
# Variables
CdRom="/dev/sr0"

# Functions
HasMedia () {
      udisks --show-info "${CdRom}" | grep "has media.*1" > /dev/null
      return $?
}

IsNotEmpty () {
      udisks --show-info "${CdRom}" | grep "blank.*0" > /dev/null
      return $?
}
# End of code

Now:
$ if IsNotEmpty; then echo "Not empty"; else echo "Empty"; fi
Not empty
$

So far, so good. Now I erase the disc:

umount "${CdRom}"
cdrecord blank=fast dev="${CdRom}"

When finished:
$ if IsNotEmpty; then echo "Not empty"; else echo "Empty"; fi
Not empty
$

So I eject the disc:
eject $CdRom

Then I insert it again and wait. Meanwhile:
$ if HasMedia; then echo "Disc found"; else echo "Disc missing"; fi
Disc missing
$ if HasMedia; then echo "Disc found"; else echo "Disc missing"; fi
Disc missing
$ if HasMedia; then echo "Disc found"; else echo "Disc missing"; fi
Disc missing
$ if HasMedia; then echo "Disc found"; else echo "Disc missing"; fi
Disc found
$

Good, disc found. Is it empty?
$ if IsNotEmpty; then echo "Not empty"; else echo "Empty"; fi
Empty
$

Great! But how can I do this without ejecting the disc? Is there some ”disc
status update” thing to do, to make the cd reader re-read the disc somehow?


Johnny Rosenberg
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