#!/bin/bash 
# copyright 2007 Gilbert Ashley <amigo@ibiblio.org>
# BashTrix uniq is an implementation of the 'uniq' command
# written in pure shell. Very few uniq options are supported.

VERSION=0.1

ERROR=0
# show program usage
show_usage() {
echo "Usage: ${0##/*} [OPTION]... [FILE]..."
echo "Try '${0##/*} --help' for more information."
exit $ERROR
}

# show program help
show_help() {
echo
echo "Usage: ${0##/*} [OPTION]... [FILE]..."
echo "  or: (cat|echo) | ${0##/*} [OPTION]..."
echo "Omit duplicate identical lines of each FILE and"
echo "print the result to standard output."
echo "With no FILE, read standard input."
echo "      --help     	display this help and exit"
echo "      --version  	output version information and exit"
exit $ERROR
}

show_version() {
echo ${0##/*}" (BashTrix) $VERSION"
echo "Copyright 2007 Gilbert Ashley <amigo@ibiblio.org>"
echo "This is free software written in pure shell."
exit $ERROR
}

# get the - options DUMMY
for WORD in "$@" ; do
	case $WORD in
		-*)  true ;
			case $WORD in
				--help) show_help ;;
				--version) show_version ;;
				-) READ_STDIN=1 ; shift ;;
			esac
		;;
	esac
done



if [[ $# -gt 0 ]] ; then
	while [[ $# -gt 0 ]] ; do
		FILE_NAME="$1"
		if [ ! -r "$1" ] ; then
			echo "Cannot find file $1" 1>&2
			exit 1
		else
			# read the lines of the file into an array LINE[$FILE_LINE_COUNT]
			FILE_LINE_COUNT=0
			LINE=
			IFS=$'\n'
			while read LINE ; do
				(( FILE_LINE_COUNT++ ))
				declare LINE[$FILE_LINE_COUNT]=$LINE
			done <"$1"
		fi
		
		# now compare each line
		COUNT=0
		while [[ $COUNT -lt $FILE_LINE_COUNT ]] ; do
			(( COUNT++ ))
			NEXT_LINE=$COUNT+1
			
			echo ${LINE[$COUNT]}
			
			if [[ "${LINE[$COUNT]}" = "${LINE[$NEXT_LINE]}" ]] ; then
				unset LINE[$NEXT_LINE]
				#FILE_LINE_COUNT=$(( $FILE_LINE_COUNT - 1 ))
				
				#COUNT=$(( $COUNT + 2 ))
				(( COUNT++ ))
			fi
		done
		
		# go to next FILE in $@
		shift
	done
else
	# piped input is presumed to be separated into lines already
	FILE_NAME="STDIN"
	# read the lines from stdin into an array LINE[$FILE_LINE_COUNT]
	FILE_LINE_COUNT=0
	LINE=
	IFS=$'\n'
	while read LINE ; do
		# add the curent line to the line counter
		(( FILE_LINE_COUNT++ ))
		declare LINE[$FILE_LINE_COUNT]=$LINE
	done
	# now compare each line
		COUNT=0
		while [[ $COUNT -lt $FILE_LINE_COUNT ]] ; do
			(( COUNT++ ))
			NEXT_LINE=$COUNT+1
			
			echo ${LINE[$COUNT]}
			
			if [[ "${LINE[$COUNT]}" = "${LINE[$NEXT_LINE]}" ]] ; then
				unset LINE[$NEXT_LINE]
				(( COUNT++ ))
			fi
		done
fi