Unformat disk size

unformat.sh

# Convert strings like '5kb', '2MB' and '500TB' to their byte equivalents
# Based on http://stackoverflow.com/questions/4399475/unformat-disk-size-strings

unformat()
{
    echo $1 | sed -e 's/b//i;s/k/*1000/i;s/m/*1000000/i;s/g/*1000000000/i;s/t/*1000000000000/i' | bc
}

Might want to add a clause for the i character, to support the difference between ISO KiB (1024) and KB (1000).