parted complain with negative number as argument for mkpart sub-command

[Chunyang Liu]

hi guys,

i want to create a partition on my disk using parted. the new partition 
will fill all remain space on the disk. as man page said, i can use 
negative number as argument to count from end of the disk.

but i found parted doesn't work. following is the command i tried:

# parted -s /dev/sdb mkpart extended 2048M '-1s'
parted: invalid option -- 1

# parted -s /dev/sdb mkpart extended 2048M '\-1s'
Error: "  1s" has invalid syntax for locations.

if in interactive mode, the above command works. but i need to script 
it. so is it a bug or it's work-aroundable?

thanks!
--
Chunyang Liu