gistfile1.sh

$ cat .git/hooks/pre-commit                                                                                                                   
#!/bin/bash                                                                                                                                   
                                                                                                                                              
                                                                                                                                              
root_dir=`git rev-parse --show-toplevel`                                                                                                      
                                                                                                                                              
for new_file in `git status --porcelain | awk '/\?\?/ { print $2 }'`;                                                                         
do                                                                                                                                            
  echo -n "$new_file ... (i)gnore, (s)kip, (a)dd [default] ? "                                                                                
                                                                                                                                              
  read add_or_ignore < /dev/tty                                                                                                               
                                                                                                                                              
  echo -en "\033[1A\033[2K" > /dev/tty                                                                                                        
                                                                                                                                              
  if [ "$add_or_ignore" == "i" ]                                                                                                              
  then                                                                                                                                        
        echo "$new_file ... ignored from now on (to undo remove it from "`git rev-parse --git-dir`/info/exclude")"                            
        echo $new_file >> `git rev-parse --git-dir`/info/exclude                                                                              
                                                                                                                                              
  else                                                                                                                                        
        if [ "$add_or_ignore" == "s" ]                                                                                                        
        then                                                                                                                                  
                echo "$new_file ... skipped (you'll be asked on next commit again)"                                                           
        else                                                                                                                                  
                echo "$new_file ... added to repo"                                                                                            
                git add $root_dir/$new_file                                                                                                   
        fi                                                                                                                                    
  fi                                                                                                                                          
                                                                                                                                              
done                                                                                                                                          
                                                                                                                                              
echo                                                                                                                                          

Pre-commit hook that forces you to either add new files to repo or to locally ignored files.