Basic computer language commands

Basic computer programming language

SHELL Statement

Purpose:

To load and execute another program or batch file. When the program finishes, control returns to the GW-BASIC program at the statement following the SHELL statement. A program executed under control of GW-BASIC is referred to as a child process.

Syntax:

SHELL [string]

Comments:

string is a valid string expression containing the name of a program to run and (optionally) command arguments.

The program name in string may have any extension that MS-DOS COMMAND.COM supports. If no extension is supplied, COMMAND will look for a .COM file, then an .EXE file, and finally, a .BAT file. If none is found, SHELL will issue a "File not found" error.

Any text separated from the program name by at least one blank space will be processed by COMMAND as program parameters.

GW-BASIC remains in memory while the child process is running. When the child process finishes, GW-BASIC continues at the statement following the SHELL statement.

SHELL with no string will go to MS-DOS. You may now do anything that COMMAND allows. When ready to return to GW-BASIC, type the MS-DOS command EXIT.

Examples:

SHELL
A>DIR
A>EXIT

Write some data to be sorted, use SHELL SORT to sort it, then read the sorted data to write a report.

10 OPEN "SORTIN.DAT" FOR OUTPUT AS #1
20 'write data to be sorted
.
.
.
1000 CLOSE 1
1010 SHELL "SORT <SORTIN.DAT >SORTOUT.DAT"
1020 OPEN "SORTOUT.DAT" FOR INPUT AS #1
1030 'Process the sorted data

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