Allow `partvis` to take stdin

partvis

@@ -20,9 +20,11 @@ sectors_to_size() {
 
 [ $EUID -gt 0 ] && echo "Must run as superuser." && exit 1
 
-for DEVICE in $(fdisk -l | grep '^Disk /' | grep -v '/dev/ram' | cut -d\  -f2 | cut -d: -f1); do
+[ -t 0 ] && DEVLIST="$(fdisk -l)" || DEVLIST="$(cat -)"
 
-  FDISKDATA="$(fdisk -l "${DEVICE}")"
+for DEVICE in $(echo "${DEVLIST}" | grep '^Disk /' | grep -v '/dev/ram' | cut -d\  -f2 | cut -d: -f1); do
+
+  [ -t 0 ] && FDISKDATA="$(fdisk -l "${DEVICE}")" || FDISKDATA="${DEVLIST}"
   COLS="$(tput cols)"
   SECTORS="$(echo "${FDISKDATA}" | grep sectors | grep -v 'sectors of' | rev | cut -d\  -f2 | rev)"
   #PARTLIST="$(echo "${FDISKDATA}" | grep '^/' | sed 's/  */ /g' | cut -d\  -f1-3)"