ptx

Generate a permuted index where the first field of each line is an index reference

$ ptx [[-r|--references]] [path/to/file]

$ ptx [[-A|--auto-reference]] [path/to/file]

$ ptx [[-w|--width]] [width_in_columns] [path/to/file]

$ ptx [[-o|--only-file]] [path/to/filter] [path/to/file]

$ ptx [[-G|--traditional]] [path/to/file]

ptx [options] [input_file]

-A, --auto-reference
    Treat all non-keyword arguments as references.

-b FILE, --break-file=FILE
    Use FILE to determine word breaks.

-f, --ignore-case
    Fold lower case to upper case for sorting.

-g, --traditional
    Act more like traditional ptx.

-i FILE, --ignore-file=FILE
    Read ignore words from FILE.

-o FILE, --output-file=FILE
    Write output to FILE.

-r, --references
    Make the first non-keyword argument the reference.

-S STRING, --sentence-end=STRING
    Set end-of-sentence delimiter to STRING.

-t, --truncation
    Truncate the input lines.

-w NUMBER, --width=NUMBER
    Use NUMBER as the output line width.

-W, --word-regexp
    Treat each line as a single word.

--help
    Display help message and exit.

--version
    Display version information and exit.

The `ptx` command generates a permuted index of the words in a file. It reads the input file and creates an output where each word in the input is rotated to the beginning of a line. This creates an index of words within their context, useful for finding occurrences of specific words and seeing the surrounding text.

`ptx` is particularly useful for creating keyword-in-context (KWIC) indexes, which are used in documentation, concordances, and other applications where it is important to quickly find and examine occurrences of specific terms. The command offers options to control the formatting of the index, including the width of the output lines, the characters used to mark rotations, and the words to ignore during indexing. It can be customized to fit diverse indexing requirements, making it a versatile tool for text processing and analysis. Options for managing line length, ignoring specified words, and controlling the rotation marker enhance its usability.

The effectiveness of `ptx` heavily relies on the quality of the input data and the specified parameters. Incorrectly configured options can lead to less useful or even misleading indexes. Consider the character encoding of your input files, as `ptx`'s handling of multi-byte characters may vary.

The `-b` option allows you to specify a file that defines custom word break characters. This is useful for languages where word boundaries are not defined by whitespace alone.

The precise output format of `ptx` can vary depending on the options used. The default format includes a prefix, the rotated word, and a suffix.

The `ptx` command has been a part of Unix-like operating systems for a long time, originating in the early days of text processing tools. Its primary purpose was to automate the generation of indexes for documents and books. Over time, implementations have been refined and extended with new features, while maintaining backward compatibility with older versions. While less commonly used for generating book indexes today due to more sophisticated software, it remains useful for smaller text processing tasks and custom indexing needs.

sort(1), grep(1)