fdisk is completely interactive, not suitable for scripting. sfdisk is a "scriptable fdisk".
Depends on what you're doing. There's workarounds for parted that allow you to do things like grow the size of a partition, but by default, you cannot shrink a partition via command line because the design philosophy of parted is that it should by default try to not delete any data. So growing via command line seems fine, but otherwise not so much.
Here on stackoverflow, there's some directions on how to use the ---pretend-input-tty flag to use parted in a script.
parted -s
orparted --script
– never prompt the userWorked for me. Thank you!