Shell Programming and Scripting

#!/bin/sh

#set -x

CHOICE=0
ITEM=0
ITEMNUM=1
ITEMCOUNT=0

CountItemsInList()
{
# Arguments
# ITEMLIST    1

  while read ITEM
  do
    ITEMCOUNT=$(expr ${ITEMCOUNT} + 1)
  done << EOF
${1}
EOF
}

ListFiles()
{
# Arguments
# ITEMLIST    1

  ITEMNUM=1
  while read ITEM; do
    echo "${ITEMNUM} : ${ITEM}"
    ITEMNUM=$(expr ${ITEMNUM} + 1)
  done << EOF
${1}
EOF
}

ItemSelected()
{
# Arguments
# ITEMLIST    1
# CHOICE    2

  I=1
  while read ITEM; do
    if [ ${2} -eq ${I} ]; then
      break
    fi
    I=$(expr ${I} + 1)
  done << EOF
${1}
EOF
}

ITEMLIST=$(ls -dr /home/*)

CountItemsInList "${ITEMLIST}"
echo "Item count: ${ITEMCOUNT}"

while [ true ]; do
  ListFiles "${ITEMLIST}"
  echo -n " Q)uit, N)ext P)revious page or numeric Choice: "
  read CHOICE
  case ${CHOICE} in
    q|Q)
      break
    ;;
    n|N)
    ;;
    p|P)
    ;;
    [0-9]*)
      if [ ${CHOICE} -le ${ITEMCOUNT} ] && [ ! ${CHOICE} = "0" ] ; then
        ItemSelected "${ITEMLIST}" "${CHOICE}"
        echo "Selected Item: ${ITEM}"
#        break
      fi
    ;;
    *)
    ;;
  esac
done

list=( $(ls -dr /home/* ) )
lines=${#list[*]}
first=${list[0]}

#no need to use external expr, ksh+bash can do it using builtin ((    ))
# = usually more safty use /bin/ksh or /bin/bash, you never know which version
# of shell the /bin/sh will be
#ITEMCOUNT=$(expr ${ITEMCOUNT} + 1)
(( ITEMCOUNT=ITEMCOUNT + 1 ))
# or
(( ITEMCOUNT+=1 ))

# it's enough
while true
do
    ...
# because true will return exit code 0, no need anymore test it