Ninja is a small, fast build system that is designed to have its input files generated by a higher-level build system. It is particularly useful for large projects where build speed is crucial. Ninja reads simple build files and executes commands to build the software. This article will guide you through the process of installing and using Ninja on a Linux system, demonstrating its importance and efficiency in managing build processes.

Examples:

1. Installing Ninja on Linux:

   To install Ninja, you can use your system's package manager. For example, on Debian-based systems like Ubuntu, you can install Ninja using the following command:

   sudo apt-get update
   sudo apt-get install ninja-build

   For Red Hat-based systems like CentOS, use:

   sudo yum install epel-release
   sudo yum install ninja-build

2. Creating a Simple Build File:

   Ninja build files are typically named build.ninja. Here is an example of a simple build.ninja file that compiles a C program:

   rule cc
    command = gcc -o $out $in
    description = Compiling $in to $out
   
   build hello: cc hello.c

   This file defines a rule named cc that uses the gcc compiler to compile C files. The build statement specifies that the target hello should be built using the cc rule and the source file hello.c.

3. Running the Build:

   To execute the build process defined in build.ninja, navigate to the directory containing the file and run:

   ninja

   Ninja will read the build.ninja file and execute the commands necessary to build the target.

4. Advanced Example with Multiple Files:

   For larger projects, you might have multiple source files. Here’s an example build.ninja file for a project with multiple C files:

   rule cc
    command = gcc -c $in -o $out
    description = Compiling $in
   
   rule link
    command = gcc $in -o $out
    description = Linking $out
   
   build foo.o: cc foo.c
   build bar.o: cc bar.c
   build main.o: cc main.c
   build myprogram: link foo.o bar.o main.o

   This file defines two rules: cc for compiling individual source files and link for linking the object files into an executable. The build statements specify how to build each object file and the final executable.

5. Cleaning Up:

   To clean up the build files generated by Ninja, you can use the following command:

   ninja -t clean

   This will remove all files built by Ninja, allowing you to start a fresh build.