script: Introduce --interactive command line option

index ed8e83d..f81e37e 100644
@@ -114,6 +114,7 @@ int	aflg = 0;
 char	*cflg = NULL;
 int	eflg = 0;
 int	fflg = 0;
+int	iflg = 0;
 int	qflg = 0;
 int	tflg = 0;
 int	forceflg = 0;

@@ -153,6 +154,7 @@ usage(FILE *out)
 		" -e, --return            return exit code of the child process\n"
 		" -f, --flush             run flush after each write\n"
 		"     --force             use output file even when it is a link\n"
+		" -i, --interactive       log only interactive shells\n"
 		" -q, --quiet             be quiet\n"
 		" -t, --timing[=<file>]   output timing data to stderr (or to FILE)\n"
 		" -V, --version           output version information and exit\n"

@@ -184,6 +186,7 @@ main(int argc, char **argv) {
 		{ "return",	no_argument,	   NULL, 'e' },
 		{ "flush",	no_argument,	   NULL, 'f' },
 		{ "force",	no_argument,	   NULL, FORCE_OPTION, },
+		{ "interactive",no_argument,	   NULL, 'i' },
 		{ "quiet",	no_argument,	   NULL, 'q' },
 		{ "timing",	optional_argument, NULL, 't' },
 		{ "version",	no_argument,	   NULL, 'V' },

@@ -197,7 +200,7 @@ main(int argc, char **argv) {
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	while ((ch = getopt_long(argc, argv, "ac:efqt::Vh", longopts, NULL)) != -1)
+	while ((ch = getopt_long(argc, argv, "ac:efiqt::Vh", longopts, NULL)) != -1)
 		switch(ch) {
 		case 'a':
 			aflg = 1;

@@ -214,6 +217,9 @@ main(int argc, char **argv) {
 		case FORCE_OPTION:
 			forceflg = 1;
 			break;
+		case 'i':
+			iflg = 1;
+			break;
 		case 'q':
 			qflg = 1;
 			break;

@@ -242,6 +248,13 @@ main(int argc, char **argv) {
 
 	isterm = isatty(STDIN_FILENO);
 
+	if (iflg && !isterm) {
+		if (cflg)
+			doexec();
+		else
+			return EXIT_SUCCESS;
+	}
+
 	if (argc > 0)
 		fname = argv[0];
 	else {