make Command in Linux

Topics Covered

Overview

In the realm of Linux, the make command is a powerful tool primarily used for building executable programs and libraries from source code. The make command automates the process of compilation, ensuring that only necessary parts of the source code are recompiled, saving both time and effort.

Syntax of make Command in Linux

The basic syntax of the make command in Linux is as follows:

Where:

  • options: These are flags that can be used to modify the behavior of the make command. Examples include -B (force rebuild), -j (jobs), etc.
  • target: The target is what you want to create. This could be the name of a final executable, a library, or even a document.

Options in make Command in Linux

  1. -B, --always-make: Unconditionally make all targets.

    For example -

    Output:

    The -B option forces make to ignore timestamps and rebuild everything.

  2. -j [jobs], --jobs[=jobs]: Specifies the number of jobs (commands) to run simultaneously.

    For example -

    Output:

    The -j option speeds up the compilation by running jobs in parallel, useful for multi-core and multi-processor systems.

  3. -f FILE, --file=FILE, --makefile=FILE: Use FILE as a makefile.

    For example -

    Output:

    The -f option allows you to specify a different Makefile other than the default one.

Example Usages

  • Basic use of make to compile a project.:

    Output:

    Explanation: Without any arguments, 'make' looks for the 'Makefile' in the current directory and executes it.

  • Using make to clean up object files and executables.:

    Output:

    Explanation: 'clean' is a conventional target in Makefiles for removing compiled files, keeping your directories neat and tidy.

Tips

  • Always double-check your Makefile for any typos or syntax errors.

  • Use the -n option before making any big changes. This will perform a dry run, showing you what would be done without actually doing it.

  • Use the -j option wisely. Although it speeds up the compilation process, using more jobs than your processor can handle might slow down your system.

Advanced Use Cases of make Command in Linux

  • Creating a shared library with make command.:

    Output:

    Explanation: 'lib' is a custom target in the Makefile, created to build a shared library.

  • Installing a compiled program using make.:

    Output:

    Explanation: 'install' is a conventional target used to copy built files into their final destinations, usually system directories.

  • Using make to run tests.:

    Output:

    Explanation: 'test' is a common target in Makefiles, typically used to run unit tests or other test suites.

Conclusion

  • The make command in Linux is a powerful tool for automating and managing the compilation of source code.

  • Make uses a 'Makefile' to define the build process.

  • Various options can be used to modify the behavior of the make command.

  • Complex projects often provide targets like 'clean', 'install', and 'test' to manage the lifecycle of the project.