#!/bin/sh -u
# Sample solution to script_practice1.txt
#------------------------------------------------------------
# Syntax:
#    $0 [ filename ]
#------------------------------------------------------------
# Purpose:
#    (See the full specifications in file script_practice1.txt )
#    Expect 0 or 1 pathname argument.  If no arguments, use "/etc/passwd".
#    Make sure the pathname is a file, is readable, and is not empty.
#    Count the characters in the file.  If the count is <= 10,
#    append the name and count to an existing file in the current
#    directory whose name comes from "$USER".
#    Print error messages and exit non-zero on errors.
#-------------------------------------------------------------
# Student Name:                  Ian! D. Allen
# Algonquin EMail Address:       alleni
# Student Number:                000-000-000
# Course Number:                 DAT2330
# Lab Section Number:            010
# Professor Name:                Ian! D. Allen
# Assignment Name/Number/Date:   Sample Exercise.
# Comment:                       This is a sample assignment label.
#         see http://teaching.idallen.com/assignment_standards.html
#-------------------------------------------------------------

# Step 1 - 2 marks - correct header (interpreter, PATH, and umask)
# Set a standard search path and non-restrictive umask.
#
PATH=/bin:/usr/bin ; export PATH
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 filename, found $# ($*)"
	exit 1
fi

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

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

# Step 4 - 6 marks
#
if [ ! -f "$file" ]; then
	echo 1>&2 "$0: '$file' is missing, inaccessible, or not a plain file"
	exit 2
fi

# Step 5 - 6 marks
#
if [ ! -r "$file" ]; then
	echo 1>&2 "$0: file '$file' is not readable"
	exit 3
fi

# Step 6 - 6 marks
#
if [ ! -s "$file" ]; then
	echo 1>&2 "$0: file '$file' is empty (zero size)"
	exit 4
fi

# Step 7 - 3 marks
# Count the characters in the file using shell input redirection.
#
count=$( wc -c <"$file" )

# Step 8 - 7 marks
# Issue a message if the character count of the file is over the limit.
# (Note the use of a variable to hold and give a name to the constant.)
#
max=10
if [ "$count" -gt "$max" ] ; then
	echo "File '$file' contains $count characters (more than $max)"
	exit 6
fi

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

# Step 9 - 7 marks
#
out="$USER" # or (less flexible) just enter your actual abcd0123 userid
if [ ! -e "$out" ]; then
	echo 1>&2 "$0: Output file '$out' is missing from current directory"
	exit 7
fi

# Step 10 - 3 marks
#
echo "File '$file' contains $count characters" >>"$out"