Standard Command Tails

The following command tails are common across all DP4 utilities:

Command Tail	Description
−DB DBNAME	Override the default database name for utilities that use a database
−DB pathname/dbname	To open a database on a different location to that specified in DFSETUP. For example: BROWSER -DB A:\MYDATA which will access the mydata database on the disk in drive a: Only use this form of the -DB command tail when absolutely necessary, and please note the following restrictions: DP4 will not allow you to open two databases with the same name in different locations. If a second program opens a database with the same name as a database that is already open it will be opened in the location the first program is using. On Windows platforms, if DP4 is running as a service in the local system account you will not be able to access databases on a network drive using this technique.
−BASEDICT	Provide access to the base dictionary tables (for expert users of DP4)
−SERVER_NAME machine_name	From version 4.523/4.619 this command tail can be used when running DP4 on client machines that use the DP4 TCP/IP network requester to select the DP4 server to run against. See -server_name Command Tail for Applications in Guide to DP4 Networking and Resilience for further information.
−HELP	Popup the help message for the utility - this will usually be similar to the Quick Reference information for the program

Command Tails for Printing

The following command tails used to control the destination of "printed" output are especially useful:

Command Tail	Description
−SCREEN	Send device output to the screen
−PRINTER	Send device output to the printer port
−FILE filename	Send device output to a file
−DEVICE device_name	Select the device to determine the characteristics for print or file output

To suppress interactive questions about which device to use for output, specify at least one of -SCREEN, -PRINTER or -FILE.

The -NOSPACE Command Tail

Several database utilities have a -NOSPACE command tail, which instructs the utility to suppress checks for sufficient disk space. Over recent years the use of this has frequently become necessary, because the DP4 function for reporting free disk space originally returned a signed 32 bit number, which meant it could never report more than 2GB free. As of release 4.622 DP4 database utilities use 64 bit file handling functions, meaning they can handle files larger than any PC operating system currently supports, and therefore there should be no need to use this command tail any more. One possible exception to this arises if you are running DP4 on a Windows 9x machine: on such machines the operating system itself may lie about the amount of space available.

Configuration File Settings as Command Tails

From version 4.620 almost any option that can be specified in the DP4 configuration file, can also be specified as a command line option. This can be very useful if you sometimes need to run a program one way, and sometimes another. For example, many batch type DP4 utilities complete they display a message box and wait for the user to press the OK button before exiting, so that the user can examine the output screen. However, if the utilitiy is run as part of a script this may not be what you want. You can use the pause=0 setting in the DP4 configuration file to suppress the pause, but then the user can no longer see the output screen. Instead you should use -pause=0 on the command line. The = is currently optional, but you are recommended always to use it.-pause on its own is equivalent to -pause=1 and the same holds for other numeric configuration file entries.