override for when to prevent automatic backups

The mainscript does check if when is set to 'manual'. If so it does not start any backups automatically.

Change-Id: I2be2f07382fd06f2f7a2ca8c39cc9547d552d40a

man/backupninja.conf.5

@@ -124,6 +124,11 @@ These values for 'when' are invalid:
   when = tuesday at 2
   when = tues at 02
 
+The value 'manual' can be set that backupninja can only be
+triggered manually.
+
+  when = manual
+
 .TP
 .SH DEFAULTS
 

src/backupninja.in

@@ -326,6 +326,8 @@ function process_action() {
    elif [ "$when" == "hourly" ]; then
       info ">>>> starting action $file (because 'when = hourly')"
       run="yes"
+   elif [ "$when" == "manual" ]; then
+      debug ">>>> skipping $file because the 'when' configuration is set to manual"
    else
       IFS=$'\t\n'
       for w in $when; do