Filters And Pipes; Command Pipes - Commodore PC Ms-Dos 3.2 User's Manual

About Commands 17
Often, it's useful to have input for a command come from a file
instead of from the keyboard. This is possible in ms-dos by using
a less-than sign (<) in your command. For example, the following
command sorts the file names and sends the sorted output to a
file called namelist:
sort
names > namelist
n
n
n
n
n
Filters and Pipes
A filter is a command that reads your input, transforms it in some
way, and then outputs it to your screen. In this manner the input
is "filtered" by the program.
ms-dos filters include: find, more, and sort. Their functions are
as follows:
find
more
sort
Searches for text in a file.
Displays the contents of a file one screenful at
a time.
Alphabetically sorts the contents of a file.
You can redirect the output from a filter into a file, or use it as
input for another filter by using pipes. The following section
explains how filters are piped together.
Command Pipes
If you want to use the output from one command as the input for
another, you can pipe the commands to MS-DOS. Piping is done by
separating commands with the pipe symbol, which is a vertical
bar (I). The following command, for example, displays an alpha
betically sorted listing of your directory on the screen:
di r I sort
The pipe sends all output generated by the dir command (on the
left side of the bar) as input to the sort command (on the right
side of the bar).
You can also use piping with redirection if you want to send the
output to a file. For example, the following command creates a
file named direct. 1st on your default drive:
ms-dos filter
commands
Piping commands
dir i sort > direct.1st