How do I read the source code of shell commands

Question

I would like to read the actual source code which the linux commands are written with  I ve gained some experience using them and now I think it s time to interact with my machine at a deeper level    I ve found some commands here http   directory fsf org wiki GNU  Unfortunately I wasn t able to find basic commands such as  ls  which seems to me easy enough to begin    How exactly do I read the source code of the simple shell commands like  ls    I m running on Ubuntu 12 04

User · Accepted Answer

All these basic commands are part of the coreutils package.

You can find all information you need here:

http://www.gnu.org/software/coreutils/

If you want to download the latest source, you should use git:

git clone git://git.sv.gnu.org/coreutils

To install git on your Ubuntu machine, you should use apt-get (git is not included in the standard Ubuntu installation):

sudo apt-get install git

Truth to be told, here you can find specific source for the ls command:

http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/ls.c

Only 4984 code lines for a command 'easy enough' as ls... are you still interested in reading it?? Good luck! :D

User · Answer

CoreUtils referred to in other posts does NOT show the real implementation of most of the functionality which I think you seek  In most cases it provides front-ends for the actual functions that retrieve the data  which can be found here   It is build upon Gnulib with the actual source code in the lib-subdirectory

User · Answer

cd    amp  amp  apt-get source coreutils  amp  amp  ls -d coreutils         You should be able to use a command like this on ubuntu to gather the source for a package  you can omit sudo assuming your downloading to a location you own

User · Answer

ls is part of coreutils  You can get it with git    git clone git   git sv gnu org coreutils   You ll find coreutils listed with other packages  scroll to bottom  on this page

User · Answer

Actually more sane sources are provided by http   suckless org look at their sbase repository   git clone git   git suckless org sbase  They are clearer  smarter  simpler and suckless  eg ls c has just 369 LOC  After that it will be easier to understand more complicated GNU code

User · Answer

Direct links to source for some popular programs in coreutils    cat  767 lines  chmod  570 lines  cp  2912 lines  cut  831 lines  date  570 lines  df  1718 lines  du  1112 lines  echo  272 lines  head  1070 lines  hostname  116 lines  kill  312 lines  ln  651 lines  ls  4954 lines  md5sum  878 lines  mkdir  306 lines  mv  512 lines  nice  220 lines  pwd  394 lines  rm  356 lines  rmdir  252 lines  shred  1325 lines  tail  2301 lines  tee  220 lines  touch  437 lines  wc  801 lines  whoami  91 lines    Full list here

User · Answer

You can have it on github using the command  git clone https   github com coreutils coreutils git   You can find all the source codes in the src folder      You need to have git installed    Things have changed since 2012  ls source code has now 5309 lines

[linux] How do I read the source code of shell commands?

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