SHELL Statement


 Example

 The following example uses the  SHELL function to execute three OS-2
 commands.

 ON ERROR GOTO ErrHandler


 Ext$ = CHR$(34) + " EXE" + CHR$(34)


 ' The child process does. DIR | FIND " EXE" | SORT


 Child$ = "dir | find " + Ext$ + "| sort"


 ProcessID = SHELL(Child$)


 PRINT "Process ID is." ProcessID


 END





 ErrHandler.


     SELECT CASE ERR


         CASE 73


             PRINT . PRINT "You cannot use the SHELL function in DOS."


         CASE ELSE


     END SELECT


     END


 SHELL Statement
 ----------------------------------------------------------------------------


 Action

 Suspends execution of the BASIC program, runs a .COM, .EXE, .BAT, or .CMD
 program, or a DOS or OS-2 command, and resumes execution of the BASIC
 program at the statement following the  SHELL statement.


 Syntax



  SHELL  commandstring

 Remarks


 The argument  commandstring must be a valid string expression that contains
 the name of a program to run, and any program arguments.

 Any .COM file, .EXE file, .BAT program, .CMD program, DOS command, or OS-2
 command that runs under the  SHELL statement is called a "child process."
 Child processes are executed by the  SHELL statement, which loads and runs a
 copy of COMMAND.COM (for DOS) or CMD.EXE (for OS-2) with the -C option.

 The -C option allows any parameters in  commandstring to be passed to the
 child process. It also allows redirection of standard input and output, and
 execution of built-in commands such as DIR and PATH.

 The program name in  commandstring can have any extension you wish. If no
 extension is supplied, COMMAND.COM (for DOS) or CMD.EXE (for OS-2) looks for
 a .COM file, then an .EXE file, and finally, a .BAT file (for DOS) or a .CMD
 file (for OS-2). If COMMAND.COM or CMD.EXE is not found, BASIC generates the
 error message File not found. BASIC does not generate an error if
 COMMAND.COM or CMD.EXE cannot find the file specified in  commandstring, but
 the operating system generates an error message.


 COMMAND.COM or CMD.EXE treat as program parameters any text separated from
 the program name by at least one blank. BASIC remains in memory while the
 child process is running. When the child process finishes, BASIC continues.

 If you omit the argument  commandstring,  SHELL gives you a new shell
 (COMMAND.COM for DOS or CMD.EXE for OS-2). You then can enter
 operating-system commands at the prompt. Use the  EXIT command to return to
 BASIC.


 Note

 If you are using OS-2, make sure that the SET COMSPEC configuration command
 in your CONFIG.SYS file specifies the path for the CMD.EXE file. If the path
 for CMD.EXE is not set, BASIC generates an error message when  SHELL
 searches for the CMD.EXE file.


 See Also

  SHELL Function


 Examples


 The following example shows how a single  SHELL statement starts up a new
 COMMAND.COM.

 ' Get a new COMMAND.COM


 ' Type EXIT at the operating system prompt to return to this program.


 SHELL




 If the name of a any executable file or command is provided as an argument
 to the  SHELL statement, that command will be executed as if it had been
 invoked from the operating-system prompt. When the program is finished,
 control returns to BASIC. The following use of the  SHELL statement
 illustrates how to display a directory listing to check the creation time of
 a file.


 SHELL "DIR | MORE"