xml

Display general help, including the list of subcommands

$ xml --help

$ xml [subcommand] [options] [path/to/input.xml|URI]

$ xml [subcommand] [options]

$ xml [subcommand] [options] [path/to/input.xml|URI] > [path/to/output]

$ xml [subcommand] --help

$ xml --version

xml [OPTIONS] [FILE...]

This conceptual command would operate on one or more XML files provided as arguments, or read XML data from standard input if no files are specified. The specific operation (e.g., validation, formatting, transformation) would be determined by the chosen options.

-v, --validate
    Validates the XML document against its internal DTD or a specified schema/DTD.

-s <schema_file>, --schema <schema_file>
    Specifies an XML Schema Definition (XSD) file for validation.

-d <dtd_file>, --dtd <dtd_file>
    Specifies an external Document Type Definition (DTD) file for validation.

-p, --pretty
    Outputs the XML document in a human-readable, indented format.

-t <xsl_file>, --transform <xsl_file>
    Applies an XSLT stylesheet to the XML document, transforming its content.

-x <xpath_expr>, --xpath <xpath_expr>
    Evaluates an XPath expression against the XML document and prints the result.

-w, --well-formed
    Checks only for XML well-formedness, without performing full validation.

-o <output_file>, --output <output_file>
    Writes the processed XML output to the specified file instead of standard output.

-h, --help
    Displays a help message detailing command usage and options, then exits.

The xml command, while not a standard standalone utility in most Linux distributions, represents a conceptual, versatile command-line tool designed for comprehensive XML processing. It consolidates functionalities typically spread across various specialized tools like xmllint, xmlstarlet, and xsltproc. A hypothetical xml command would provide capabilities for validating XML documents against DTDs or XML Schemas, pretty-printing XML for enhanced readability, applying XSLT transformations, and querying XML data using XPath expressions. Its purpose would be to streamline interaction with XML directly from the terminal, making it invaluable for developers, system administrators, and anyone automating tasks involving XML files. Such a tool would handle common parsing errors, provide informative diagnostics, and support various input/output options, aiming to simplify complex XML operations within shell scripts and command-line workflows.

The 'xml' command is not a standard, pre-installed utility found in most Linux distributions. The description provided here is conceptual, outlining functionalities that a unified XML command-line tool would offer, based on common capabilities of existing specialized tools. Users typically rely on specific packages like libxml2-utils (providing xmllint) or xmlstarlet for actual XML processing tasks on Linux.

A well-designed xml command would offer comprehensive error handling, providing clear and concise diagnostic messages for XML documents that are either malformed or fail validation. These messages would typically include specific line and column numbers, along with a description of the error (e.g., unexpected end tag, undeclared entity, schema validation failure). This level of detail is crucial for efficient debugging and ensuring the integrity of XML data processed via the command line.

Since the 'xml' command is conceptual and not a standard utility, it does not have a conventional development history. However, its theoretical inception stems from the widespread adoption of XML across various computing domains since the late 1990s. This prevalence led to the development of numerous specialized tools for XML parsing, validation, transformation, and querying (e.g., libxml2, Apache Xerces, Saxon). A unified 'xml' command would conceptually represent a consolidation effort, aiming to provide a single, user-friendly interface to these diverse functionalities, driven by the need for more efficient command-line XML manipulation in scripting and automation environments.

xmllint(1): A command-line tool for parsing, validating, and pretty-printing XML documents, part of the libxml2 library., xmlstarlet(1): A versatile command-line toolkit for XML transformation, validation, formatting, and querying using XPath., xsltproc(1): A command-line XSLT processor, typically used for applying XSLT stylesheets to XML documents., grep(1): General-purpose pattern matching tool, occasionally used for simple text searches within XML files., sed(1): Stream editor, can perform basic text manipulations on XML files, though not XML-aware.