Makefile+VersionControl
Download as PPTX, PDF1 like492 views
1. The document discusses building software on Linux systems using build systems like Make and version control systems like Git. It explains that build systems take source code and build dependencies to create executable files, while version control systems track changes to files over time. 2. Make is an original build system that uses Makefiles containing rules with targets, prerequisites, and commands. Configure scripts ensure required system components are available. 3. Git is a popular version control system (VCS) that tracks changes to files and allows recovering old versions. It uses a Git directory to store changes and a staging area between the working directory and repository.
Makefile+VersionControl
- 1. LUG -4: BUILDING BLOCKS Building Software on Linux systems
- 2. Build? • The software meaning of ‘building’ is pretty much the same as the everyday meaning - to take raw materials and create something useful out of them. int c; int d; max(); Subl Jmpl Addl Jmp Popl Addl import java.lang.* Source files (The Work Stuff) int a; int b; sum(); import java.util.* BUILD PROCESS Executable File (The fun stuff)
- 3. Why use a Build System • It makes your workflow reproducible. • It makes life easier for end-users. • It helps you document the full software installation process.
- 4. Make • Classic, original build system released in 1977 for UNIX. • Uses a formatted set of instructions, stored in a file called a Makefile. Source Code targetfile: source com mand abc.zip: curl counties.zipMakefile RESULT
- 5. Makefiles • A makefile consists of sequential rules. • A rule consists of a target, required components, and commands. • If the prerequisites are satisfied, the command is performed when the specific target is called.. target : prerequisites ; command(s)
- 6. An Example CC = gcc CFLAGS = -c -Wall all: main main: main.o randrange.o $(CC) main.o randrange.o -o password-pronounce main.o: src/main.c $(CC) $(CFLAGS) src/main.c randrange.o: src/randrange.c $(CC) $(CFLAGS) src/randrange.c clean: rm -rf *o password-pronounce install: cp password-pronounce /usr/bin/ uninstall: all is called first, and checks for the dependency main. Since main has not been built yet, the system looks for a rule to build it. Control flows recursively down the file, until the first target is built. The rest of the build then completes upwards
- 7. What’s Missing? • System prerequisites, such as compilers, linkers and assemblers. • Even if these are installed, make may not know the right place to look for them. • That’s where configure comes in.
- 8. Configure • Configure is an executable shell script that matches components on the computer to those required by the Makefile • Automates system portability, by making sure that everything is in the right place
- 9. Version Control • Version control is a system that records changes to a file or set of files over time so that you can recall specific versions later • A VCS allows you to revert files back to a previous state, revert the entire project back to a previous state, review changes made over time, see who last modified something that might be causing a problem, who introduced an issue and when, and more • Using a VCS also means that if you screw things up or lose files, you can generally recover easily
- 10. The Git VCS
- 11. Git Basics • Git uses a Git directory, a working directory, and a staging area. • The Git directory is where everything is actually stored. It’s where Git keeps your project’s database. • The working directory is the directory you’re currently working in. It’s one version of your project. • The staging area is a file that Git uses to keep track of the changes you’ve made in the working directory.
- 12. Git Basics The git workflow is as follows: • You modify files in your working directory. • You stage the files, adding snapshots of them to your staging area. • You do a commit, which takes the files as they are in the staging area and stores that snapshot permanently to your Git directory. Any given file in a git repository can be only be in one of those three states.
- 13. Try out what you learnt! • We’ve prepared a (small) complete project that includes a configure script, a makefile, and is stored as a git repository. • To get it, type this in your git or bash terminal: git clone https://github.com/puranjay/password-pronounce • Use the readme file to get it up and running on a Linux machine.