fish: In interactive mode, improve error message for help of unknown command (RHBZ#1497475)

fish/fish.c

@@ -1169,13 +1169,8 @@ issue_command (const char *cmd, char *argv[], const char *pipecmd,
     r = rc_remote (remote_control, cmd, argc, argv, rc_exit_on_error_flag);
 
   /* Otherwise execute it locally. */
-  else if (STRCASEEQ (cmd, "help")) {
-    if (argc == 0) {
-      display_help ();
-      r = 0;
-    } else
-      r = display_command (argv[0]);
-  }
+  else if (STRCASEEQ (cmd, "help"))
+    r = display_help (cmd, argc, argv);
   else if (STRCASEEQ (cmd, "quit") ||
            STRCASEEQ (cmd, "exit") ||
            STRCASEEQ (cmd, "q")) {
@@ -1239,6 +1234,7 @@ display_builtin_command (const char *cmd)
 
   if (STRCASEEQ (cmd, "help")) {
     printf (_("help - display a list of commands or help on a command\n"
+              "     help --list\n"
               "     help cmd\n"
               "     help\n"));
     return 0;
@@ -1251,8 +1247,12 @@ display_builtin_command (const char *cmd)
     return 0;
   }
   else {
-    fprintf (stderr, _("%s: command not known, use -h to list all commands\n"),
-             cmd);
+    fprintf (stderr, _("%s: command not known: "), cmd);
+    if (is_interactive) {
+      fprintf (stderr, _("use 'help --list' to list all commands\n"));
+    } else {
+      fprintf (stderr, _("use -h to list all commands\n"));
+    }
     return -1;
   }
 }

fish/fish.h

@@ -76,7 +76,7 @@ extern int alloc_disk (const char *filename, const char *size,
 extern int parse_size (const char *str, off_t *size_rtn);
 
 /* in help.c */
-extern void display_help (void);
+extern int display_help (const char *cmd, size_t argc, char *argv[]);
 
 /* in prep.c */
 struct prep_data {

fish/guestfish.pod

@@ -1365,11 +1365,14 @@ other words, they are not part of the L<guestfs(3)> API.
 
  help
  help cmd
+ help -l|--list
 
 Without any parameter, this provides general help.
 
 With a C<cmd> parameter, this displays detailed help for that command.
 
+With I<-l> or I<--list>, this list all commands.
+
 =head2 exit
 
 =head2 quit

fish/help.c

@@ -38,30 +38,47 @@
  * improved if we knew how many drives had been added already, and
  * whether anything was mounted.
  */
-void
-display_help (void)
+int
+display_help (const char *cmd, size_t argc, char *argv[])
 {
-  if (guestfs_is_config (g))
-    printf (_(
+  if (argc == 0) {
+    if (guestfs_is_config (g))
+      printf (_(
 "Add disk images to examine using the ‘-a’ or ‘-d’ options, or the ‘add’\n"
 "command.\n"
 "Or create a new disk image using ‘-N’, or the ‘alloc’ or ‘sparse’ commands.\n"
 "Once you have done this, use the ‘run’ command.\n"
-              ));
-  else
-    printf (_(
+                ));
+    else
+      printf (_(
 "Find out what filesystems are available using ‘list-filesystems’ and then\n"
 "mount them to examine or modify the contents using ‘mount-ro’ or\n"
 "‘mount’.\n"
-              ));
+                ));
 
-  printf ("\n");
+    printf ("\n");
 
-  printf (_(
+    printf (_(
 "For more information about a command, use ‘help cmd’.\n"
 "\n"
 "To read the manual, type ‘man’.\n"
-            ));
+              ));
 
-  printf ("\n");
+    printf ("\n");
+
+    return 0;
+  }
+  else if (argc == 1) {
+    if (STREQ (argv[0], "--list") || STREQ (argv[0], "-l")) {
+      /* List all commands. */
+      list_commands ();
+      return 0;
+    }
+    else
+      return display_command (argv[0]);
+  }
+  else {
+    fprintf (stderr, _("use 'help', 'help <cmd>' or 'help -l|--list' to list all commands\n"));
+    return -1;
+  }
 }