Error: pg_config executable not found.
 
 Please add the directory containing pg_config to the PATH
 
 or specify the full executable path with the option:
 
 
 
  python setup.py build_ext --pg-config /path/to/pg_config build ...
 
 
 
 or with the pg_config option in 'setup.cfg'.
 
 ----------------------------------------
 Command python setup.py egg_info failed with error code 1 in /tmp/pip-build/psycopg2

Error: Unable to find 'pg_config' file in '/usr/pgsql-9.1/bin/'

$ which pg_config
 /usr/pgsql-9.1/bin/pg_config