anchor.diff:    Default is `backup:$NAME`.
   
   TARGET_DIR::
  -  Base path of directory where to store files to be backed up by a backup software.
  +  Base path to a directory where the files should be stored to be backed up by a backup software.
     Default is `/var/tmp/backup`.
   
   TEMP_DIR::
  -  Base path of directory where to store temporary files for prebackup scripts.
  +  Base path to a directory where temporary files for prebackup scripts should be stored.
     Default is `/tmp/prebackup`.
   
   VERBOSE::
     Log even debug messages (yes/no)? Default is `no`.
   
   target_dir::
  -  Path of directory where to store files for a particular “job” (i.e. generated by the sourced script) to be backed up by a backup software.
  +  Path of directory where files for a particular “job” should be stored (i.e. files generated by the sourced script) to be backed up by a backup software.
     Default is `$TARGET_DIR/$NAME`.
   
   temp_dir::
  -  Path of directory where to store temporary files for the sourced script.
  +  Path of directory where temporary files for the sourced script should be stored.
   
   
   == Predefined Functions
  
positive.code: Then you must define functions `pre-backup`, `post-backup` and optionally `setup`.
  
  setup()::
    If defined, then this function is executed before each `pre-backup()` and `post-backup()`, in the same environment.
    You may use it to check if required variables are set (using `required-var()`), to define some common variables or anything else that should be run before `pre-backup()` and `post-backup()`.
  
  pre-backup()::
    This function is executed when you run the script as a file named `pre-backup` (e.g. using symlink) or with argument `-c pre-backup`.
  
negative.code: 
  RUN_AS::
    User to run the script.
    If you execute the script as a different user than the one specified by `$RUN_AS`, it will switch to the specified user using `su`.
    Default is empty, i.e. do not switch user.
  
  SYSLOG::
  