*** /home/albinus/src/tramp/lisp/tramp.el.~1~
--- /home/albinus/src/tramp/lisp/tramp.el
***************
*** 6106,6111 ****
--- 6106,6118 ----
  
    ;; Set the environment.
    (tramp-message vec 5 "Setting default environment")
+ 
+   ;; On OpenSolaris, there is a bug when HISTFILE is changed in place
+   ;; <http://bugs.opensolaris.org/view_bug.do?bug_id=6834184>.  We
+   ;; apply the workaround.
+   (if (string-equal (tramp-get-connection-property vec "uname" "") "SunOS 5.11")
+       (tramp-send-command vec "unset HISTFILE"))
+ 
    (let ((env (copy-sequence tramp-remote-process-environment))
	  unset item)
      (while env