#!/bin/sh -u
# DAT2330 03W Unix Final - Thursday Script Sample Solution
#  $0  [ file ]
# -IAN!  idallen@ncf.ca

# Step 1 - 2 marks - correct header (interpreter, PATH, and umask)
# Set a standard search path and non-restrictive umask.
#
export PATH=/bin:/usr/bin
umask 022

# Step 2 - 7 marks
# Exit the script if more than one argument is given.
#
if [ $# -gt 1 ]; then
	echo 1>&2 "$0: expecting one optional pathname, found $# ($*)"
	exit 1
fi

# Step 3 - 4 marks
# Use the Unix password file if no arguments are given.
#
if [ $# -eq 0 ]; then
	argfname='/etc/passwd'
else
	argfname="$1"
fi

# Make sure the pathname is not a directory, is not empty, is readable.

# Step 4 - 6 marks
#
if [ -d "$argfname" ]; then
	echo 1>&2 "$0: pathname '$argfname' is a directory (want a file)"
	exit 2
fi

# Step 5 - 6 marks
#
if [ ! -s "$argfname" ]; then
	echo 1>&2 "$0: file '$argfname' is missing or empty"
	exit 3
fi

# Step 6 - 6 marks
#
if [ ! -r "$argfname" ]; then
	echo 1>&2 "$0: file '$argfname' is not readable"
	exit 4
fi

# Step 7 - 3 marks
# Count the characters in the file.
#
bytecnt=$( wc -c <"$argfname" )

# Prompt and read a size limit.
# Exit the script if the user enters nothing.

# Step 8 - 3 marks
#
echo 1>&2 "Enter a numeric size limit:"
read mynum || exit 1

# Step 9 - 6 marks
#
if [ -z "$mynum" ] ; then
	echo 1>&2 "$0: empty input count - nothing done"
	exit 5
fi

# Step 10 - 7 marks
# Issue a message if the character count of the file is <= size limit.
#
if [ "$bytecnt" -le "$mynum" ] ; then
	echo "Pathname '$argfname' character count $bytecnt is <= $mynum"
	exit 6
fi

# Make sure that a file named with your Algonquin userid exists.
# Append the count of characters in the $argfname to the $fout file.

# Step 11 - 7 marks
fout="$USER" # or just enter your actual abcd0123 userid
if [ ! -e "$fout" ]; then
	echo 1>&2 "$0: Output file '$fout' is missing from current directory"
	exit 7
fi

# Step 12 - 3 marks
#
echo "I counted $bytecnt characters in file '$argfname'" >>"$fout"