ptx Command in Linux

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The ptx command in Linux produces the permuted index of an input file. A permuted index organizes text so that every word in a sentence or phrase can be used to locate it. It rearranges the words in all possible ways, allowing any word to be searched while displaying the full sentence or phrase. This approach is commonly called a Keyword in Context (KWIC) index. It helps quickly locate where specific keywords appear in large documents.

Table of Contents

Here is a comprehensive guide to the options available with the ptx command −

• Syntax of ptx Command
• ptx Command Options
• Examples of ptx Command in Linux

Syntax of ptx Command

The syntax of the ptx command in Linux is as follows −

ptx [options] [file]

In the above syntax, the [options] field is used to specify the various options to modify the command’s output. The [file] field is used to specify the input file that needs to be processed.

ptx Command Options

The options of the Linux ptx command are listed below −

Examples of ptx Command in Linux

In this section, the usage of the ptx command in Linux will be discussed with examples.

• Producing Permuted Index of a File
• Producing Traditional Permuted Index
• Producing Permuted Index in TeX Format
• Producing Permuted Index with an Ignore File
• Generating Auto Reference
• Using Flag Truncation
• Generating Output in roff Format
• Displaying Reference on the Right Side
• Using Word Regular Expression
• Ignoring Case Sensitivity
• Setting Gap Size between Output Fields
• Producing Permuted Index by Keywords File
• Setting the Output Width
• Treating the First Field of each Line as a Reference
• Displaying Usage Help

Producing Permuted Index of a File

Before producing the permuted index of the file, let’s check the content of the sample file. The sample file is simple and contains the following contents −

To produce the permuted index of this file, use the ptx command in the following way −

ptx sample.txt

Producing Traditional Permuted Index

To produce the traditional permuted index of file, use the -G or --traditional option −

ptx -G sample.txt

The output will behave like the traditional ptx implementation from System V, with minor differences in formatting.

Producing Permuted Index in TeX Format

To produce a permuted index in the TeX format for use in LaTeX typesetting, use the -T or --format option −

ptx -T sample.txt

Producing Permuted Index with an Ignore File

To exclude common words from being used as keywords, create an ignore file. For example, to exclude The, a, and of from the permuted index, add these words in the ignore file.

Now, to produce the permuted index ignore the contents of the file ignore.txt file, use the ptx command with -i or --ignore-file option −

ptx -i ignore.txt sample.txt

Generating Auto Reference

To automatically generate the reference for each line, use the -A or --auto-reference option −

ptx -A sample.txt

Using Flag Truncation

To use flag truncation, use the -F or --flag-truncation option

ptx -F "=" sample.txt

Using the above command, the truncated lines will be flagged with the (=) sign. By default, the lines are truncated with a (/).

Generating Output in roff Format

To generate a permuted index in the roff format, use the -O or --format option −

ptx -O sample.txt

Displaying Reference on the Right Side

To display reference on the right side, use the -R or --right-side-refs option with the ptx command −

ptx -R sample.txt

Using Word Regular Expression

To use the word regular expression, the -W or --word-regexp option is used with the ptx command. For example, to display index lines that contain quick and lazy words, use the following command −

ptx -W "quick|lazy" sample.txt

Ignoring Case Sensitivity

To ignore the case sensitivity while sorting the index, use the -f or --ignore-case option −

ptx -f sample.txt

Setting Gap Size between Output Fields

To set the gap size between the output fields, use the -g or --gap-size option with the size number in columns. For example, to set the gap size to 7, use the ptx command in the following way −

ptx -g 7 sample.txt

Producing Permuted Index by Keywords File

To generate the permuted index based on the keywords mentioned in the file, use the -o or --only-file option −

ptx -o keywords.txt sample.txt

Setting the Output Width

To set the output width, use the -w or --width option with the number of columns. For example, to set the output width to 100 columns, use the following command −

ptx -w 100 sample.txt

Treating the First Field of each Line as a Reference

To treat the first field of each line as a reference, use the -r or --references option −

ptx -r sample.txt

Displaying Usage Help

To display the usage help of the ptx command, use the --help option −

ptx --help

Conclusion

The ptx command in Linux is used to create a permuted index of a file, rearranging its words in all possible combinations to facilitate easy keyword searching. It allows various options to customize the output, such as generating references, formatting in different types (TeX, roff), ignoring specific words, and adjusting column width. Additionally, it supports features like case-insensitive sorting, setting gap sizes between output fields, and using regular expressions for keyword matching.