Challenge

Shell Scripting

Objective: Shell scripting is a basic skill every Linux developer has Proficiency Level: Advanced

We require a script to do some "processing" for every kernel released:

• First, make it work

• Second, optimize it

We need the following working directory structure

    ...
    |- LinuxKernelDevelopmentProcessChallenge
      |- kernelimages  (directory)
      |- preworkspace  (directory)
      |- postworksapce (directory)
      |- main.sh (our script)
      |- stats.pre (text file)
      |- stats.post (text file)
      |- intel.contributors (text file)

Script Arguments

The script will receive 3 arguments: the file location, version of the kernel and the file type

user $ myscript.sh <internet/local> <x.x.xx> <xz|gz>

If file location is the internet then use this repository to grab the kernel tar file:

• https://www.kernel.org/pub/linux/kernel/v4.x/

  and download it to kernelimages directory.

If file location is local then use kernelimages directory to grab the kernel tar file

Processing

We will gather statistics and do some work in 2 phases, right after we have decompressed the kernel file under the preworkspace directory and after we make some changes to its directory structure under postworkspace, statistics will be populated in 2 different files under our top working directory, their names will be:

1. stats.pre

2. stats.post

Pre Processing

Take kernel image from kernelimages directory and decompress under the preworkspace directory. We will require the following information under stats.pre files:

File Names

# of README* (files as README.Locking also count)
# of Kconfig
# of Kbuild
# of Makefiles
# of .c files
# of .h files
# of .pl files
# of others files
Total number of files

File Content

# of ocurrences for Linus
# of directories found under arch/
# of ocurrences for kernel_start
# of ocurrences for __init
# of files in its filename containing the word gpio
# of ocurrences for #include <linux/module.h>

Some Tasks To Do

Sort in alphabetical order all the inclusion of libraries using this format #include only under drivers/i2c/ directory, please make sure you identify all files you have modified, you will need their identity in the post processing phase

Let's populate our file called intel.contributors under our top level working directory directory, search for all Intel contributors matching @intel.com and identify the file where their name was located, then write one line per contributor, cannot be repeated e.g.

Path/to/file.c | Sara Sharp
Path/to/file.c | Darren Hart

Post Processing

Create 3 directories under postworkspace and move all files from preworkspace where kernel was decompressed according to the file extensions:

files_c, all .c files
files_h, all .h files
files_others, all other files

In all 3 directories, if we have files with the same name, add a number as identifier that will increase by 1 as required, e.g.

README_1
README_2

Some Tasks To Do

1. Add your name to the beginning, middle and end of every .c file

2. In all files substitute #include for every #include found

3. Fix your #include's order for the files coming from driver/i2c

We will need the following information under stats.post files:

File Names

# of READMEs
# of Kconfig
# of Kbuild
# of Makefiles
# of .c files
# of .h files
# of .pl files
# of others files
Total number of files

File Content

# of ocurrences having "Linus" string
# of ocurrences having "kernel_start" string
# of ocurrences having "__init" string
# of files in its filename containing the word "gpio"
# of ocurrences having "#include <linux/module.h>"
# of ocurrences having "#include <linux/learningscripting.h>"

Results

A message of Pass / Fail should be printed to stdout for each of the following:

• Our Total number of files is the same in both stats.pre and stats.post