--- a/rvinterf/asyncshell/Makefile	Sun Oct 23 17:26:48 2016 +0000
+++ b/rvinterf/asyncshell/Makefile	Sun Oct 23 18:38:07 2016 +0000
@@ -1,8 +1,8 @@
 CC=	gcc
 CFLAGS=	-O2 -I../include
 PROG=	fc-shell
-OBJS=	at.o init.o main.o oneshot.o parse.o pktsort.o poweroff.o rxctl.o \
-	sendarb.o sendsp.o tchcmd.o tchplay.o tchrec.o usercmd.o
+OBJS=	at.o help.o init.o main.o oneshot.o parse.o pktsort.o poweroff.o \
+	rxctl.o sendarb.o sendsp.o tchcmd.o tchplay.o tchrec.o usercmd.o
 LIBS=	../libasync/libasync.a ../libg23/libg23.a
 INSTBIN=/usr/local/bin
 INSTHELP=/usr/local/share/freecalypso

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rvinterf/asyncshell/help.c	Sun Oct 23 18:38:07 2016 +0000
@@ -0,0 +1,86 @@
+/*
+ * This module implements the fc-shell help facility.
+ */
+
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <strings.h>
+#include <stdlib.h>
+
+char help_file_pathname[] = "/usr/local/share/freecalypso/fc-shell.help";
+
+show_help_topic(topic)
+	char *topic;
+{
+	FILE *f;
+	char linebuf[256];
+	char *cp, *np;
+	int flag;
+
+	f = fopen(help_file_pathname, "r");
+	if (!f) {
+		perror(help_file_pathname);
+		return(-1);
+	}
+	for (;;) {
+		if (!fgets(linebuf, sizeof linebuf, f)) {
+			printf("error: help topic \"%s\" not found\n", topic);
+			fclose(f);
+			return(-1);
+		}
+		if (linebuf[0] != '=' || linebuf[1] != '=' || linebuf[2] != '=')
+			continue;
+		for (cp = linebuf + 3; isspace(*cp); cp++)
+			;
+		for (np = cp; *cp && !isspace(*cp); cp++)
+			;
+		if (*cp)
+			*cp++ = '\0';
+		if (!strcmp(np, topic))
+			break;
+	}
+	for (flag = 0; fgets(linebuf, sizeof linebuf, f); ) {
+		if (linebuf[0] == '=' && linebuf[1] == '=' &&
+		    linebuf[2] == '=') {
+			if (flag)
+				break;
+			else
+				continue;
+		}
+		fputs(linebuf, stdout);
+		flag = 1;
+	}
+	fclose(f);
+	return(0);
+}
+
+void
+cmd_help(argstr)
+	char *argstr;
+{
+	char *argv[3], dbltopic[34];
+	int argc, rc;
+
+	rc = parse_interactive_command_into_argv(argstr, argv, 0, 2, &argc);
+	if (rc < 0)
+		return;
+	switch (argc) {
+	case 0:
+		show_help_topic("main");
+		break;
+	case 1:
+		show_help_topic(argv[0]);
+		break;
+	case 2:
+		if (strlen(argv[0]) <= 16 && strlen(argv[1]) <= 16) {
+			sprintf(dbltopic, "%s:%s", argv[0], argv[1]);
+			show_help_topic(dbltopic);
+		} else
+			printf("error: no such help topic\n");
+		break;
+	default:
+		fprintf(stderr, "internal error in cmd_help(): bad argc\n");
+		abort();
+	}
+}

--- a/rvinterf/asyncshell/usercmd.c	Sun Oct 23 17:26:48 2016 +0000
+++ b/rvinterf/asyncshell/usercmd.c	Sun Oct 23 18:38:07 2016 +0000
@@ -13,6 +13,7 @@
 
 extern void cmd_disable();
 extern void cmd_enable();
+extern void cmd_help();
 extern void cmd_poweroff();
 extern void cmd_sendat();
 extern void cmd_send_interactive();
@@ -35,6 +36,7 @@
 	{"disable", cmd_disable},
 	{"enable", cmd_enable},
 	{"exit", cmd_exit},
+	{"help", cmd_help},
 	{"poweroff", cmd_poweroff},
 	{"quit", cmd_exit},
 	{"send", cmd_send_interactive},