How to Use the Command 'licensor' (with examples)
The licensor command-line utility is designed to streamline the process of generating open-source license texts. It reads a specified license template and writes it to the standard output, which can then be redirected to create or update license files in your software projects. This tool also provides functionalities to customize licenses with placeholders, specify copyright holders, include license exceptions, and list available licenses and exceptions. For software developers and project maintainers, managing licenses is crucial for ensuring legal compliance and establishing clear rights and responsibilities.
Use Case 1: Writing the MIT License to a File Named LICENSE
Code:
licensor MIT > LICENSE
Motivation:
Suppose you have just started a new open-source project and wish to apply the MIT License, a popular and permissive free software license. To make the project officially open-source, a LICENSE file must be included in your repository. This example demonstrates how to effortlessly generate this file using licensor.
Explanation:
licensor: The command itself, initiating the license generation process.MIT: Specifies the type of license you wish to write into the file. The MIT License is known for its simplicity and broad permissions, making it a common choice for open-source projects.>: Shell operator to redirect the output of the command to a file.LICENSE: The name of the file where the license content should be written. This is a conventional name used in many projects to contain the license text.
Example Output:
The LICENSE file will contain the standard MIT License text, allowing users of the software to use, copy, modify, merge, publish, distribute, sublicense, and sell copies of the software with the standard conditions provided in the MIT License.
Use Case 2: Writing the MIT License with a Placeholder Copyright Notice
Code:
licensor -p MIT > LICENSE
Motivation:
Incorporating a placeholder for the copyright notice within a license document is beneficial when multiple contributors or subsequent project maintainers need to personalize the copyright holder’s name without altering the general license text. This use case shows how to create a license file that prompts users to customize the copyright notice.
Explanation:
licensor: Invokes the command for generating license text.-p: A flag indicating that the output should include placeholders where the user can later insert specific information, such as the copyright holder’s name and date.MIT: Specifies the MIT License.>: Redirects the output to a specified file.LICENSE: The destination file where the license, complete with placeholders, will be written.
Example Output:
The generated LICENSE file will contain the MIT License text along with placeholders, such as “
Use Case 3: Specifying a Copyright Holder Named Bobby Tables
Code:
licensor MIT "Bobby Tables" > LICENSE
Motivation:
When creating a license file, a specific individual or organization’s name is often included as the copyright holder to clearly indicate ownership and responsibility. This example shows how to automatically insert the name “Bobby Tables” into the license, enhancing the clarity of who retains copyright.
Explanation:
licensor: The command for license text generation.MIT: Specifies the MIT License."Bobby Tables": A string argument representing the name of the copyright holder to be embedded within the license text. Enclosed in quotes to treat the text as a single string, even if spaces are present.>: Directs the output into a file.LICENSE: The file where the customized license text will be recorded.
Example Output:
The LICENSE file generated will contain the MIT License with “Bobby Tables” listed as the copyright holder, along with the standard terms granting users rights to use, modify, and distribute the software.
Use Case 4: Specifying License Exceptions with a WITH Expression
Code:
licensor "Apache-2.0 WITH LLVM-exception" > LICENSE
Motivation:
Sometimes a license may need to include certain exceptions to standard terms, such as when using specific files or components that have distinct permissions or restrictions. License exceptions help in clearly defining such scenarios. This example depicts how to use the licensor command to efficiently append exceptions to licenses, enhancing clarity and compliance.
Explanation:
licensor: The command used for generating license text."Apache-2.0 WITH LLVM-exception": A string that specifies the desired license (Apache-2.0) along with any additional exceptions, in this case, the LLVM-exception, which permits some redistribution uses not normally allowed under the standard Apache License.>: Used to redirect the generated output.LICENSE: The file to capture the license content with exceptions.
Example Output:
The LICENSE file will include the Apache 2.0 License text alongside the LLVM exception, providing an expanded and tailored licensing agreement that reflects the unique requirements of the project.
Use Case 5: Listing All Available Licenses
Code:
licensor --licenses
Motivation:
Developers often need to compare and contrast different licenses to decide which best fits their project’s needs. This command provides an overview of all supported licenses, saving time and aiding informed decision-making.
Explanation:
licensor: Executes the command-line utility to interact with license data.--licenses: A flag that specifies the command to list all available license types supported by thelicensortool, aiding users in selecting a suitable choice for their project.
Example Output:
The command outputs a list of all standard licenses available within the tool, such as MIT, Apache-2.0, GPL-3.0, etc., providing a comprehensive directory to choose from.
Use Case 6: Listing All Available Exceptions
Code:
licensor --exceptions
Motivation:
Exceptions alter the standard terms of licenses and can be critical in meeting specific legal requirements or project needs. Listing these exceptions helps developers understand what adjustments can be legally integrated into their chosen license.
Explanation:
licensor: Calls the utility for license management.--exceptions: A flag indicating the command to list all available exceptions supported bylicensor, helping users identify potential add-ons to their licenses.
Example Output:
The command returns a list of available exceptions, such as the LLVM-exception, providing users with options for customizing their licensing terms.
Conclusion:
The licensor command serves as a versatile tool for managing licensing in software projects. From generating basic license files to offering customized copyright notices and managing exceptions, it simplifies an essential part of software development. Each use case offers the flexibility needed to address the wide variety of scenarios that developers encounter when managing licenses. With the licensor tool, ensuring compliance with open-source obligations becomes a smoother and more organized task.
