impagina: Added documentation and a --help argument

impagina

@@ -1,10 +1,28 @@
 #!/bin/sh
 
+usage() {
+	_name="$(basename "$0")"
+	cat << EOF
+Utilizzo: ${_name} [nomePDF]
+
+Esempi:
+
+	${_name} MeccanicaRazionale.pdf
+
+Per bug contattare f.minnocci@studenti.unipi.it
+I ringraziamenti per l'idea originale vanno a http://poisson.phc.dm.unipi.it/~dilillo
+EOF
+exit $1
+}
+
+main() {
 	# Initialize variables
-input="$1"
-inputMul4="/tmp/${input%.pdf}-Mul4.pdf"
-outputImpaginato="${input%.pdf}-Impaginato.pdf"
+	input="$(realpath "$1")"
+	basename="$(basename "$1")"
+	inputMul4="/tmp/${basename%.pdf}-Mul4.pdf"
+	outputImpaginato="${basename%.pdf}-Impaginato.pdf"
 	empty="/tmp/empty.pdf"
+	echo "$input $basename $inputMul4 $outputImpaginato" > ~/log
 	n="$(pdftk "$input" dump_data | grep NumberOfPages | cut -d' ' -f2)"
 
 	# Add empty pages
@@ -25,3 +43,17 @@ done
 	pdftk "$inputMul4" cat $range output "$outputImpaginato"
 
 	rm "$empty" "$inputMul4"
+}
+
+if [ -z "$1" ] ; then
+	printf "Non hai specificato nessun file...\n\n" && usage 1
+else
+	case "$1" in
+	-h|--help)
+		usage 0 ;;
+	-*)
+		error "Opzione invalida: $1" ;;
+	*)
+		main "$@" ;;
+	esac
+fi