This command allows Windows Command Processor or UNIX shell commands to be given from APL. )CMD is a synonym of )SH. Either command may be given in either environment (Windows or UNIX) with exactly the same effect. )CMD is probably more natural for the Windows user. This section describes the behaviour of )CMD and )SH under Windows. See Execute (UNIX) Command for a discussion of the behaviour of these commands under UNIX.
The system functions ⎕SH and ⎕CMD provide similar facilities but may be executed from within APL code.
Note that under Windows, you may not execute )CMD without a command. If you wish to, you can easily open a new Command Prompt window outside APL.
Example
)cmd dir
Volume in drive C is OS
Volume Serial Number is B438-9B76
Directory of C:\Users\Pete\Documents\Dyalog APL-64 17.0 Unicode Files
23/06/2018 15:59 <DIR> .
23/06/2018 15:59 <DIR> ..
23/06/2018 14:53 181,488 default.dlf
13/06/2018 20:13 1,262,296 def_uk.dse
14/06/2018 14:36 108,976 UserCommand20.cache
3 File(s) 1,552,760 bytes
2 Dir(s) 101,371,437,056 bytes free
If cmd issues prompts and expects user input, it is ESSENTIAL to explicitly redirect input and output to the console. If this is done, APL detects the presence of a ">" in the command line and runs the command processor in a visible window and does not direct output to the pipe. If you fail to do this your system will appear to hang because there is no mechanism for you to receive or respond to the prompt.
Example
)CMD DATE <CON >CON
(Command Prompt window appears)
Current date is Wed 19-07-1995
Enter new date (dd-mm-yy): 20-07-95
(Command Prompt window disappears)
Implementation Notes
The argument of )CMD is simply passed to the appropriate command processor for execution and its output is received using an unnamed pipe.
By default, )CMD will execute the string ('cmd.exe /c',Y) where Y is the argument given to )CMD. However, the implementation permits the use of alternative command processors as follows:
Before execution, the argument is prefixed and postfixed with strings defined by the APL parameters CMD_PREFIX and CMD_POSTFIX. The former specifies the name of your command processor and any parameters that it requires. The latter specifies a string which may be required. If CMD_PREFIX is not defined, it defaults to the name defined by the environment variable COMSPEC followed by "\c". If COMSPEC is not defined, it defaults to COMMAND.COM or CMD.EXE as appropriate. If CMD_POSTFIX is not defined, it defaults to an empty vector.
Note:
This function is disabled and instead generates a DOMAIN ERROR if the RIDE_SPAWNED parameter is non-zero. This is designed to prevent it being invoked from a RIDE session which does not support this type of user interface. For further details, see the RIDE User Guide.