What is the purpose of the WORKDIR instruction in a Dockerfile?

The WORKDIR instruction in a Dockerfile is used to set the working directory for any subsequent instructions that follow it. When you specify a path with the WORKDIR instruction, it creates the specified directory if it does not already exist, and any subsequent commands like RUN, CMD, ENTRYPOINT, or COPY will be executed in this directory context. This is particularly useful for organizing files and ensuring that commands execute in the correct location within the filesystem of the container.

By establishing a working directory, developers can avoid specifying absolute paths in each following instruction, making the Dockerfile cleaner and easier to read. Additionally, it provides a consistent environment for commands that depend on being in a specific directory, which enhances workflow and reduces the chances of file not found errors or similar issues.

While defining environment variables, setting the default user, or specifying the base image are important aspects of a Dockerfile, they do not relate to the function of setting the working directory, which is the specific role of the WORKDIR instruction.