use double quotes in default interpreter command

data/yad.1

@@ -173,7 +173,7 @@ Don't close dialog if \fIEscape\fP was pressed.
 Print result for any of the return codes. This option doesn't work if timeout was reached or \fIEscape\fP was pressed.
 .TP
 .B \-\-use-interp=\fI[INTERP]\fP
-All commands runs unter specified interpreter. Default is \fIbash -c '%s'\fP. This option can reduse quoting in commands. If \fI%s\fP is specified, it will be replaced by the command.
+All commands runs unter specified interpreter. Default is \fIbash -c "%s"\fP. This option can reduse quoting in commands. If \fI%s\fP is specified, it will be replaced by the command.
 Otherwise command will be appended to the end of command line.
 .TP
 .B \-\-uri-handler=\fICMD\fP

src/option.c

@@ -1545,7 +1545,7 @@ yad_options_init (void)
   options.data.keep_icon_size = FALSE;
   options.data.def_resp = YAD_RESPONSE_OK;
   options.data.use_interp = FALSE;
-  options.data.interp = "bash -c '%s'";
+  options.data.interp = "bash -c \"%s\"";
 #ifndef STANDALONE
   options.data.uri_handler = g_settings_get_string (settings, "open-command");
 #else