Piping Explained

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SORT <unsorted.txt

This sorts the text in UNSORTED.TXT and outputs the resulting text to the console display. This is great if you only need one filter to process your text...

Following is a more capable form of the above example:

type unsorted.txt | SORT

Here, the piping operator, "|" effectively connects the output of the TYPE command with the input of the SORT filter, creating what is known as a pipe. This example demonstrates a simple one-filter pipe that is functionally identical to the first example.

Pipes can be created containing any number of filters. For example, the MORE filter could be added to our pipe to pause each output screen of sorted text:

type unsorted.txt | SORT | MORE

In the above examples output is being sent to the console display. A pipe's output can also be sent to a file using the output redirection operator, ">" as shown here:

SORT <unsorted.txt >sorted.txt

Here, SORT takes it's input from UNSORTED.TXT, sorts it and writes it to the file, SORTED.TXT. If the file, SORTED.TXT already exists, it gets overwritten with the new data. If you merely want to append the new data to a file that already exists, use the append redirection operator ">>" instead as shown here:

SORT <unsorted.txt >>sorted.txt

Here, the same is accomplished using the piping operator:

type unsorted.txt | SORT >>sorted.txt

TEXTools Pipes

The above is generally how pipes and filters work at the command prompt. Text originates from some source, goes through one or more filters and is output either to the console display or redirected to a file.

TEXTools takes this same paradigm of pipes and filters and simply wraps it in a Windows user interface in which the pipe is transposed from one that is laid out horizontally (as those depicted above) to one that is vertical. A TEXTools pipe is thus presented to the user as multiple lines, each one representing a single filter in the pipe. A pipe that parses the words in the input text, pads each one to equal lengths and then joins them into 3 columns would therefore be formatted onto three lines as follows:

ParseWords
PadLinesRight ' '
JoinLines 3

This transposing of a pipe in the GUI version of TEXTools however does not occur in TEXTools Command Line, (TCL), which, as its name implies, is used at the command line or command prompt. In TCL, the above pipe would still be presented horizontally as shown by the following example:

type in.txt | TCL "ParseWords | PadLinesRight ' ' | JoinLines 3" >out.txt

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