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From: ear@wpi.wpi.edu (Eric A Rasmussen)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Redirection and piping
Message-ID: <6250@wpi.wpi.edu>
Date: 13 Dec 89 01:58:32 GMT
References: <89345.110313MHS108@PSUVM.BITNET>
Reply-To: ear@wpi.wpi.edu (Eric A Rasmussen)
Organization: Worcester Polytechnic Institute, Worcester ,MA
Lines: 38

In article <89345.110313MHS108@PSUVM.BITNET> MHS108@PSUVM.BITNET (Mark Solsman) writes:
>
>   Can any one out there explain how to use the redirection and the pipeline
>features with ms-dos?

It's relatively simple.

>  redirects standard output from a program, which would normally go to the
   screen, to whereever you redirect it to.

For example, typing "main > prn" at the dos prompt would cause the output
from the program main to go to the printer.  You can also redirect output to a
file.

<  redirects standard input to a program, generally from a file, instead of
   taking the input from the keyboard.

For example, typing "main < commands.txt" at the dos prompt would cause the
program main to act as if you had typed all the characters in the file
commands.txt from the keyboard.

|  takes the output from a command or program, instead of a file or device, and
   passes (pipes) it along to a second program for subsequent processing. 
   (Note that I'm not so familiar with this feature, but I know how to use it.) 

For example, typing "dir | more" at the dos prompt has about the same effect
as "dir/p", but in this case you are using the program MORE to display the
output from DIR one page at a time by intercepting its output and only letting
you see 24 lines of it at a time before making you press a key to continue. 
When you use the /p option with the DIR command, you are using a built in
feature of DIR.  (Note that for this to work, you must have the program 
MORE.whatever-the-extension-on-it-is somewhere in your directory path.)

Hope this helps.
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