Ptx is a command-line tool that is used to generate permuted indexes of words in one or more text files. A permuted index is a type of index that lists all the words in a text file or set of files in alphabetical order, with the corresponding page numbers where each word appears.
The ptx utility is commonly used by document indexing systems to generate a list of keywords and their locations in a document or set of documents. This allows users to quickly locate specific words or phrases within a document, and is particularly useful for large, complex documents where manual searching would be time-consuming or impractical.
When run, ptx reads one or more input files and generates an output file containing the permuted index. By default, ptx sorts the index alphabetically, with each word followed by a list of page numbers where that word appears. It can also be configured to sort by frequency, by page number, or by some combination of these criteria.
In addition to generating permuted indexes, ptx can also be used to generate concordances, which are similar to permuted indexes but list the words in the order in which they appear in the text, rather than in alphabetical order. Concordances are often used in literary analysis to study the use of language and themes in a text.
ptx Command Examples
1. Generate a permuted index where the first field of each line is an index reference:
# ptx --references path/to/file
2. Generate a permuted index with automatically generated index references:
# ptx --auto-reference path/to/file
3. Generate a permuted index with a fixed width:
# ptx --width=width_in_columns path/to/file
4. Generate a permuted index with a list of filtered words:
# ptx --only-file=path/to/filter path/to/file
5. Generate a permuted index with SYSV-style behaviors:
# ptx --traditional path/to/file
Overall, ptx is a powerful and flexible tool for generating permuted indexes and concordances from text files. While it may not be a tool that is used by every user, it can be extremely valuable in situations where document indexing and keyword searching are important, such as in research, academia, or publishing.