Prints the root of the current catkin workspace, or prints nothing and exits with non-zero exit code if not in a catkin workspace.

catkin_toplevel.py

#!/usr/bin/env python

from __future__ import print_function

import os


CMAKELISTS_FILE_NAME = 'CMakeLists.txt'


def dir_is_ws_src(d):
  ''' Returns true if the directory d is the src directory of a catkin
      workspace. False otherwise. '''
  dirs = os.listdir(d)
  if CMAKELISTS_FILE_NAME in dirs:
    cmakelists_path = os.path.join(d, CMAKELISTS_FILE_NAME)        
    return (os.path.islink(cmakelists_path)                
            and 'toplevel' in os.readlink(cmakelists_path))
  return False


def dir_is_ws_root(d):
  ''' Return True is the directory d is the root of a catkin workspace. False
      otherwise. '''
  dirs = os.listdir(d)
  if 'src' in dirs:        
    src_dir = os.path.join(d, 'src')        
    return dir_is_ws_src(src_dir)    
  return False


def main():
  home_dir = os.path.expanduser('~')
  
  while True:        
    cur_dir = os.path.abspath(os.curdir)        
    
    # We don't want to progress any further if we're not under a user's        
    # home directory. If you're not making your workspaces under a home        
    # directory... start.        
    if cur_dir == home_dir or home_dir not in cur_dir:            
      return 1        
      
    if dir_is_ws_root(cur_dir):            
      print(cur_dir)           
      return 0        
      
    # Go up a directory.        
    os.chdir('..')
    
    
if __name__ == '__main__':    
  status = main()    
  exit(status)