/DeleteItemsNotInNewManifest (/dmf): Default is True, meaning during upgrade of a currently installed HC, helpItems listed ...

/DeleteItemsNotInNewManifest (/dmf): Default is True, meaning
  during upgrade of a currently installed HC, helpItems listed
  in the current manifest but absent from the new manifest will be
  deleted from the system. False is uncommon but it means no
  checking for needed deletes will be performed, so speed will
  be faster. Sometimes we know there will be nothing to delete.
/HelpItemId (/hid): The id tag value as it appears near the top
  inside the metadata file text, plus the extension (such as .htm).
  /act ReportAllIds shows these full id values.
/FilterSubstring (/fil): The /act ReportAllIds can return
  thousands of records to the console. Each record contains
  both path and file name strings. A string value for /fil
  will report only those records in which the /fil substring value
  is found (matching is case insensitive). For instance, to
  see all installed HCs, use /fil .manifest.xml filtering.
/IncludeNotExcludeNamespaces (/inens): Can filter which HC namespaces
  are processed by /act InstallAllHCs. Tightly coordinated with
  param /inetf. This is a comma delimited list, such as...
      /inens MyCompany.OurProductA,MyCompany.OurProductB
/IncludeNotExcludeTrueFalse (/inetf): Tells /act InstallAllHCs whether
  the /inens list is of namespaces to include or exclude. The default
  is an empty /inens values and a 'false' value for /inetf, to mean
  no filtering. If 'true', the only namespaces processed will be
  those in the /inens list.
/LocaleId (/loc): The lcid tag value as it appears near the top inside
  the manifest file text.
  Default is 0, meaning no locale id is being specified, treat as all.
  For instance, 1033 means American English (en-US).
  No /mns nor /hid value is sufficient without the correct associated
  /loc value.
  Giving /loc with /act UninstallAllHCs will uninstall all HCs only
  for that one locale, nothing else will be uninstalled.
/LockOverruled (/lor): 'true' tells action DeleteOneHCLock to delete
  the lock for the HC unconditionally, if the lock exists. The
  delete should happen regardless of whether the lock is young or has
  expired, and regardless of the guid value inside the lock file.
  Default value is 'false'.
/ManifestNamespace (/mns): The id tag value inside the manifest file.
  This excludes the suffix '.manifest', and the file extension '.xml'.
/ManifestFileRootPath (/mrp): Overrides default path.
  The default path is reported below.
  This value should go no deeper than to the parent of the locale directory.
  The locale directory should not be included.
/OmitNonBody (/onb): Default is false. Normally reports of the
  text of a helpItem show exactly what is stored in the system,
  including extras the system may add. But if True is given,
  extra processing will be done to trim away those extras.
/SearchStringToFind (/sch): Such as perhaps the four characters 'sort' to
  find to find all help items discussing how to sort data.
/SleepSeconds (/sle): This program pauses for this many seconds starting the
  moment this parameter is detected. Rarely used.
/ThrottleCountBetweenSleeps (/tcb): Default is -1, meaning no Sleeps.
  The purpose of this optional parameter is to make the action sleep at
  some interval, to give other applications time to use the computer's
  resources without having to compete against this. If a Help Collection
  contains 500 items, and this /tcb value is 20, then the action will
  take 25 sleeps before finishing.
  This parameter and the /tsd parameter must be used together in order
  for either to have any non-default effect.
/ThrottlePerSleepDurationMs (/tsd): Default is -1, meaning no Sleeps.
  See /tcb. This /tsd parameter specifies the duration of each sleep,
  in milliseconds. Thus 1000 equals 1 second. Values longer than
  approximately ten seconds may be quietly forced down to ten seconds.
  Perhaps /tcb 40 /tsd 2000 might suit some cases.
/TimerSp (/tim): 'true' means this program will complete quickly, because it
  only tells the SharePoint Timer service to do all the work. Applies only
  to Install and Upgrade, ignored for all other action types. 'false' means
  this program will not complete until all processing is completed.
  Default is 'false'.
  Caution: In some cases where two actions can overlap by processing the
  same HC items simultaneously, it might be safer to use /act InstallAllHCs
  with /inetf true /inens Comp.ProdA,Comp.ProdB, instead of two close
  together successive runs of /act InstallOneHC.
/UpgradeRequiresNewerManifestVersion (/unv): An input Help Collection as a
  whole will be judged as newer than the version already installed (if already
  installed) based on the version tag values in the existing versus new
  Manifest file. 'true' is recommended and is the default.
  'true' means if both manifests have the same version value, then upgrading
  of this HC will be skipped as a harmless NoOp.
  'false' means each helpItem in both the existing and new HC will have its
  version checked individually against its counterpart. It is recommended
  that the version in the new manifest be increased every time you want to
  upgrade one or more helpItems in the HC.
RETURN CODES (integer values for .Bat ERRORLEVEL):
    0  =  No Error.
    8  =  Error.
CONSOLE OUTCOME CODES (printed to console through stderr):
    4  =  MergeSuccess
   32  =  MergeNothingDoneOK
  256  =  MergeError
  For example, if /act SearchOneHC finds no matches, the integer value for
MergeNothingDoneOK will be printed to the console, and 0 will be returned.
  []  Parameter names are case insensitive.
  []  For /act InstallAllHCs, the /loc param is usually omitted,
  or given explicitly as 0.
  []  The default /mrp value is shown below (if available).
  Immediately after this root path must be a locale id subdirectory
  (example, 1033\\).
  Third party Help Collections should be installed under this locale path.
  []  Examples or command line templates:
HcInstal.exe /act ReportAllIds
HcInstal.exe /act InstallOneHC /mrp C:\mydir\ /loc 1033 /mns comp.proda