Q40592: SHELL Redirected to NUL Device Suppresses MS-DOS Message

Article: Q40592
Product(s): See article
Version(s): 2.00 2.01 3.00 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom B_GWBasicI | mspl13_basic
Last Modified: 14-DEC-1989

From a BASIC program, you can invoke the SHELL statement to execute an
MS-DOS command. Normally, many MS-DOS commands give you a confirmation
message. If you want to suppress the message (thus making the SHELL
operation less visible), you can redirect the standard MS-DOS output
to the NUL device.

The following is an example:

   SHELL "copy file1 file2 > NUL"

The above statement copies file1 to file2 and redirects the success
report "1 file(s) copied" to the NUL device, which is never displayed.

This information applies to the following products:

1. Microsoft QuickBASIC Versions 2.00, 2.01, 3.00, 4.00, 4.00b,
   and 4.50 for the IBM PC

2. Microsoft BASIC Compiler Versions 6.00 and 6.00b for MS OS/2
   and MS-DOS

3. Microsoft BASIC PDS Version 7.00 for MS-DOS and MS OS/2

4. Microsoft GW-BASIC Interpreter Versions 3.20, 3.22, and 3.23
   for MS-DOS

In MS-DOS, the greater-than sign, ">", redirects standard output to
standard input. The less-than sign, "<", redirects standard input to
standard output.

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