How to git ignore files that are already tracked

for all people who use  eclipse , they always don't want to track some kind of files like (.properties,.metadata ...) that are automatically created by eclipse .
also the other problem is that git will not ignore a file that was already tracked before a rule was added to the file  .gitignore to ignore it 

So what is the Solution ?

In such a case , you should follow these two steps :

1. files must be un-tracked, usually with 
git rm --cached filename
2. now they do not show up as "changed" but still show as untracked files in git status , so add some  exclude rules into .git/info/exclude  file in your repository
    

In case of Eclipse ,  do these two steps  to completely remove files and repositories from being tracked :

1. execute this script after git add . :
   

   git rm --cached *.pydevproject
   git rm --cached *.project
   git rm --cached *.metadata
   git rm --cached */bin/**
   git rm --cached */tmp/**
   git rm --cached *.tmp
   git rm --cached *.bak
   git rm --cached *.swp
   git rm --cached *~.nib
   git rm --cached *local.properties
   git rm --cached *.classpath
   git rm --cached *.settings/*
   git rm --cached *.loadpath
   git rm --cached *org.eclipse.wst.common.component
   git rm --cached *org.eclipse.wst.common.project.facet.core.xml
   git rm --cached *.properties
   git rm --cached *.orig
   git rm --cached *.classpath
   git rm --cached *.xml
   git rm --cached *.jar
   git rm --cached *.class
   



2. add this code to .git/info/exclude  file in your repository
   

   # git ls-files --others --exclude-from=.git/info/exclude
   # Lines that start with '#' are comments.
   # For a project mostly in C, the following would be a good set of
   # exclude patterns (uncomment them if you want to use them):
   # *.[oa]
   # *~
   
   #Eclipse#
   ###################
    
   *.pydevproject
   *.project
   *.metadata
   */bin/*
   */bin/
   */tmp/**
   *.tmp
   *.bak
   *.swp
   *~.nib
   *local.properties
   *.classpath
   *.settings/*
   *.settings/
   *.loadpath
   *org.eclipse.wst.common.component
   *org.eclipse.wst.common.project.facet.core.xml
   *.properties
   *.orig
   *.classpath
   *.xml
   
   # Package Files #
   ##################
   *.jar
   *.war
   *.ear
   
   # Compiled source #
   ###################
   *.com
   *.class
   *.dll
   *.exe
   *.o
   *.so
   
   # Packages #
   ############
   # it's better to unpack these files and commit the raw source
   # git has its own built in compression methods
   *.7z
   *.dmg
   *.gz
   *.iso
   *.jar
   *.rar
   *.tar
   *.zip
   
   # Logs and databases #
   ######################
   *.log
   *.sqlite
   
   # OS generated files #
   ######################
   .DS_Store
   .DS_Store?
   ._*
   .Spotlight-V100
   .Trashes
   Icon?
   ehthumbs.db
   Thumbs.db
   

These rules are not committed with the repository so they are not shared with others. This method can be used for locally-generated files that you don't expect other users to generate, like files created by your editor.

for more informations visit the official github site.


I hope that this sample tutorial can help someone else :)