Попытка подключиться к серверу по SSH и получить key_load_public: Нет такой ошибки файла или каталога

Это letterSpace , которое можно запросить и установить через интерфейс Perl.

В документации перечислено несколько ресурсов, с которыми можно обращаться таким образом:

   $value = $term->resource ($name[, $newval])
       Returns the current resource value associated with a given name and
       optionally sets a new value. Setting values is most useful in the
       "init" hook. Unset resources are returned and accepted as "undef".

       The new value must be properly encoded to a suitable character
       encoding before passing it to this method. Similarly, the returned
       value may need to be converted from the used encoding to text.

       Resource names are as defined in src/rsinc.h. Colours can be
       specified as resource names of the form "color+", e.g.
       "color+5". (will likely change).

       Please note that resource strings will currently only be freed when
       the terminal is destroyed, so changing options frequently will eat
       memory.

       Here is a likely non-exhaustive list of resource names, not all of
       which are supported in every build, please see the source file
       /src/rsinc.h to see the actual list:

         answerbackstring backgroundPixmap backspace_key blurradius
         boldFont boldItalicFont borderLess buffered chdir color cursorBlink
         cursorUnderline cutchars delete_key depth display_name embed ext_bwidth
         fade font geometry hold iconName iconfile imFont imLocale inputMethod
         insecure int_bwidth intensityStyles iso14755 iso14755_52 italicFont
         jumpScroll letterSpace lineSpace loginShell mapAlert meta8 modifier
         mouseWheelScrollPage name override_redirect pastableTabs path perl_eval
         perl_ext_1 perl_ext_2 perl_lib pointerBlank pointerBlankDelay
         preeditType print_pipe pty_fd reverseVideo saveLines scrollBar
         scrollBar_align scrollBar_floating scrollBar_right scrollBar_thickness
         scrollTtyKeypress scrollTtyOutput scrollWithBuffer scrollstyle
         secondaryScreen secondaryScroll shade skipBuiltinGlyphs skipScroll
         term_name title transient_for transparent tripleclickwords urgentOnBell
         utmpInhibit visualBell

Дополнительная литература:

• URxvt Perl Extensions (Jérôme Belleman)
• rxvt-unicode (Gentoo)