#!/bin/sh -u
# This script compares two strings: an argument and stdin.
#------------------------------------------------------------
# Syntax:
#    $0 string
#------------------------------------------------------------
# Purpose:
#    Exit non-zero if there is not exactly one command line argument.
#    Prompt for and read a string.  Compare it with the single command
#    line argument and print whether or not it matches.  Exit zero
#    only if the strings match.  Exit non-zero otherwise.
#-------------------------------------------------------------
# -IAN! idallen@idallen.ca

# Use standard search path, friendly umask, ASCII collating and sorting.
# Set the language and character set to be ASCII/C standard.
#
PATH=/bin:/usr/bin ; export PATH
LC_COLLATE=C ; export LC_COLLATE
LANG=C ; export LANG
umask 022

# Make sure we have exactly one command line argument.
# If not, echo the count and incorrect input back to the user on stderr.
#
if [ $# -ne 1 ] ; then
    echo 1>&2 "$0: Expecting one argument, found $# ($*)"
    exit 1
fi

# Echo the user's input argument back to the user before using it.
#
echo "Argument string is: '$1'"

# Warn the user of the argument string is empty (no characters).
#
if [ -z "$1" ] ; then
    echo 1>&2 "$0: Warning: your argument string is empty (no characters)"
fi

# Prompt for input (always on stderr) and read another string.
# Echo the user's input back to the user before using it.
#
echo 1>&2 "Enter one line of input:"
read string
echo "Input string is: '$string'"

# Warn the user of the string read in is empty (no characters).
#
if [ -z "$string" ] ; then
    echo 1>&2 "$0: Warning: your input string is empty (no characters)"
fi

# Compare the two strings and exit non-zero if they differ.
#
if [ "$1" != "$string" ] ; then
    echo "Argument string '$1' does not match input string '$string'."
    exit 1
fi

echo "The two strings match each other: '$1'"

# The script exits with exit status of last command executed.