Added auto_show installation helper

ok.sh

@@ -185,6 +185,7 @@ if [[ $called == $0 ]]; then
     echo "arguments, if you need to customize (these can also be set via arguments/environment):"
     echo "  prompt <prompt> Use the supplied prompt (e.g. prompt '> ')"
     echo "  prompt_default  Prompt default when issueing running ok without arguments"
+    echo "  auto_show       Perform 'ok list-once' every time the prompt is shown (modifies \$PROMPT_COMMAND)"
     echo "  verbose         Enable verbose mode"
     echo "  quiet           Enable quiet mode"
     echo
@@ -193,15 +194,19 @@ else
     unset _OK_C_HEADING; unset _OK_C_NUMBER; unset _OK_C_COMMENT; unset _OK_C_COMMAND; unset _OK_C_PROMPT
     unset _OK_PROMPT; unset _OK_PROMPT_DEFAULT; unset _OK_VERBOSE; unset _OK__LAST_PWD
     # Process some installation helpers
+    re_list_once=$'ok list-once'
     while (( $# > 0 )) ; do
         case $1 in
             prompt) if [[ $# -ge 2 ]]; then export _OK_PROMPT=$2; shift; else echo "the prompt argument needs the actual prompt as 2nd argument"; fi;;
             prompt_default) export _OK_PROMPT_DEFAULT=1;;
             verbose)        export _OK_VERBOSE=2;;
             quiet)          export _OK_VERBOSE=0;;
+            auto_show)      if [[ ! $PROMPT_COMMAND =~ $re_list_once ]]; then export PROMPT_COMMAND="$PROMPT_COMMAND
+$re_list_once"; fi;;
             *) echo "Ignoring unknown argument '$1'";;
         esac
         shift
     done
+    unset re_list_once
 fi
 unset called