Index: cli/cli-decode.c
===================================================================
RCS file: /cvs/src/src/gdb/cli/cli-decode.c,v
retrieving revision 1.118
diff -u -p -r1.118 cli-decode.c
--- cli/cli-decode.c	10 Apr 2013 15:11:12 -0000	1.118
+++ cli/cli-decode.c	16 Apr 2013 11:49:40 -0000
@@ -1556,6 +1556,9 @@ lookup_cmd (const char **line, struct cm
     }
   else
     {
+      if (strlen(*line) != 0 && c->type == set_cmd && **line != ' ' )
+     error (_("Argument must be preceded by space."));
+
       /* We've got something.  It may still not be what the caller
          wants (if this command *needs* a subcommand).  */
       while (**line == ' ' || **line == '\t')

Index: ChangeLog
===================================================================
RCS file: /cvs/src/src/gdb/ChangeLog,v
retrieving revision 1.15421
diff -u -p -r1.15421 ChangeLog
--- ChangeLog	15 Apr 2013 23:53:37 -0000	1.15421
+++ ChangeLog	16 Apr 2013 11:45:38 -0000
@@ -1,3 +1,8 @@
+2013-04-16  Muhammad Bilal  <mbilal@codesourcery.com>
+
+	PR gdb/10462
+	* cli/cli-decode.c (lookup_command): Checked a space before argument.
+	
 2013-04-15  Doug Evans  <dje@google.com>
 
 	* dwarf2read.c (struct dwo_file): Replace member "cus" with "cu".