#!/bin/sh

# dfn: df normalized, or df not noisy, or df nicely, or df new
#
# Whatever you want to call it, this script makes df useful again.
# It removes read-only disks for Time Machine backups, system volumes
# that can't be modified, unbrowsable volumes, and other stuff you don't
# really care about.
#
# Instead, you get the same drives that you see on your Mac desktop in an
# easy-to-read format. Use the options variable below to change the options
# used for output (for example, -h instead of -H).

# options used to show disk usage: no inodes and sizes in powers of 10
options="-PH"

if [ ! -z "$*" ]; then
	echo "usage: edit options variable in `basename $0` script or use /bin/df"
	exit 1
fi

# the only part of the root file system that's modifiable
system="/System/Volumes/Data"

# create an array of local disks (using mount name)
mount | \
	grep -v "read-only" | grep -v "nobrowse" | grep -v "smbfs" | \
	sed -E 's/.* on (.*) \(.*/\1/' > /tmp/disks
IFS=$'\n' read -d '' -r -a disks < /tmp/disks
declare -a local
for disk in "${disks[@]}"; do
	# names in the array are quoted to preserve spaces in the names
	local+=(`printf %q "$disk"`)
done

eval "/bin/df $options $system ${local[@]}" 

# create an array of remote disks (using mount point)
mount | \
	grep "smbfs" | \
	sed 's/ on .*//' > /tmp/shares
IFS=$'\n' read -d '' -r -a shares < /tmp/shares
declare -a remote
for share in "${shares[@]}"; do
	remote+=(`printf %q "$share"`)
done

if [ ${#remote[@]} -gt 0 ]; then
	# remove the first line and filesystem prefixes from output
	echo ""
	eval "/bin/df $options ${remote[@]}" | sed '1d' | sed 's/^\/\/.*@//'
fi

# clean up
rm /tmp/disks /tmp/shares