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#!/bin/ksh
# Removes items from your $HOME/.todo list
# Written by Wayne Pollock, Tampa Florida 1997
#set -x       # uncomment this line to turn on debuging mode!

PATH=/bin
umask 077

FILE=$HOME/.todo
TempFile=/tmp/todo.$$
rev=$(tput rev)        # The byte string to turn on reverse video mode
norm=$(tput rmso)      # The byte string to turn off reverse video mode

if [ $# != 1 ]
then
    echo "$rev ### Error:  type 'didit #' to remove item # from todo list" >&2
    echo $norm >&2
    exit -1
fi

if [ ! -s $FILE ]
then
    echo "The todo list is empty; there's nothing to do!" >&2
    echo >&2
    exit -1
fi

sed "$1 d"  <$FILE  >$TempFile 2>/dev/null

# Checking that the new file size is exactly one less than the old file size:

OLD_SIZE=$(cat $FILE |wc -l)        # Note how to run a command, saving the
NEW_SIZE=$(cat $TempFile |wc -l)    # output in a string!

if [ "$OLD_SIZE" != "$(($NEW_SIZE + 1))" ]    # Note the in-line arithmetic!
then
    echo "$rev ### Error: todo file not modified!" >&2
    echo $norm >&2
    rm -f $TempFile 2>/dev/null
    exit -1
fi

mv $TempFile $FILE