Python Best way to add to sys path relative to the current running script

Question

I have a directory full of scripts  let s say project bin   I also have a library located in project lib and want the scripts to automatically load it  This is what I normally use at the top of each script      usr bin python from os path import dirname  realpath  sep  pardir import sys sys path append dirname realpath   file       sep   pardir   sep    lib          now the real code import mylib   This is kind of cumbersome  ugly  and has to be pasted at the beginning of every file  Is there a better way to do this   Really what I m hoping for is something as smooth as this      usr bin python import sys path from os path import pardir  sep sys path append relative pardir   sep    lib    import mylib   Or even better  something that wouldn t break when my editor  or someone else who has commit access  decides to reorder the imports as part of its clean-up process      usr bin python --relpath append    lib import mylib   That wouldn t port directly to non-posix platforms  but it would keep things clean

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I m using    import sys os sys path append os getcwd

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This one works best for me  Use   os path abspath       On mac it should print something like     Users  lt your username gt   lt path to where you at gt     To get the abs path to the current wd  this one is better because now you can go up if you want  like this   os path abspath          And now      Users  lt your username gt      So if you wanna import utils from here   Users  lt your username gt    All you ve got left to do is   import sys sys path append os path abspath

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If you don t want to edit each file   Install you library like a normal python libray or Set PYTHONPATH to your lib   or if you are willing to add a single line to each file  add a import statement at top e g   import import my lib   keep import my lib py in bin and import my lib can correctly set the python path to whatever lib you want

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There is a problem with every answer provided that can be summarized as  quot just add this magical incantation to the beginning of your script  See what you can do with just a line or two of code  quot  They will not work in every possible situation  For example  one such magical incantation uses   file    Unfortunately  if you package your script using cx Freeze or you are using IDLE  this will result in an exception  Another such magical incantation uses os getcwd    This will only work if you are running your script from the command prompt and the directory containing your script is the current working directory  that is you used the cd command to change into the directory prior to running the script   Eh gods  I hope I do not have to explain why this will not work if your Python script is in the PATH somewhere and you ran it by simply typing the name of your script file  Fortunately  there is a magical incantation that will work in all the cases I have tested  Unfortunately  the magical incantation is more than just a line or two of code  import inspect import os import sys    Add script directory to sys path    This is complicated due to the fact that   file   is not always defined   def GetScriptDirectory        if hasattr GetScriptDirectory   quot dir quot            return GetScriptDirectory dir     module path    quot  quot      try            The easy way  Just use   file              Unfortunately    file   is not available when cx Freeze is used or in IDLE          module path     file       except NameError          if len sys argv   gt  0 and len sys argv 0    gt  0 and os path isabs sys argv 0                module path   sys argv 0          else              module path   os path abspath inspect getfile GetScriptDirectory               if not os path exists module path                     If cx Freeze is used the value of the module path variable at this point is in the following format                     PathToExeFile   NameOfPythonSourceFile   This makes it necessary to strip off the file name to get the correct                   path                  module path   os path dirname module path      GetScriptDirectory dir   os path dirname module path      return GetScriptDirectory dir  sys path append os path join GetScriptDirectory     quot lib quot    print GetScriptDirectory    print sys path   As you can see  this is no easy task

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You can run the script with python -m from the relevant root dir  And pass the   modules path  as argument   Example    python -m module sub module main    Notice there is no   py  at the end     Another example     tree    Given this file structure    -- bar         --   init   py         -- mod py  -- foo      --   init   py      -- main py    cat foo main py from bar mod import print1 print1      cat bar mod py def print1        print  In bar mod py      python foo main py    This gives an error Traceback  most recent call last     File  foo main py   line 1  in  lt module gt      from bar mod import print1 ImportError  No module named bar mod    python -m foo main    But this succeeds In bar mod py

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When we try to run python file with path from terminal  import sys  For file name file name sys argv 0   For first argument dir  sys argv 1  print  quot File Name      argument dir     quot  format file name  dir   Save the file   test py   Runing system  Open terminal and go the that dir where is save file  then write python test py  quot  home saiful Desktop bird jpg quot   Hit enter Output  File Name  test  Argument dir   home saiful Desktop bird jpg

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This is what I use   import os  sys sys path append os path join os path dirname   file      lib

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I see a shebang in your example  If you re running your bin scripts as   bin foo py  rather than python   bin foo py  there s an option of using the shebang to change  PYTHONPATH variable   You can t change environment variables directly in shebangs though  so you ll need a small helper script  Put this python sh into your bin folder      usr bin env bash export PYTHONPATH  PWD lib exec   usr bin python         And then change the shebang of your   bin foo py to be   bin python sh

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If you don t want to change the script content in any ways  prepend the current working directory   to  PYTHONPATH  see example below   PYTHONPATH    PYTHONPATH alembic revision --autogenerate -m  First revision    And call it a day

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Create a wrapper module project bin lib  which contains this   import sys  os  sys path insert 0  os path join      os path dirname os path dirname os path realpath   file        lib     import mylib  del sys path 0   sys  os   Then you can replace all the cruft at the top of your scripts with      usr bin python from lib import mylib

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Using python 3 4  Barring the use of cx freeze or using in IDLE     import sys from pathlib import Path  sys path append Path   file    parent    lib

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I use  from site import addsitedir  Then  can use any relative directory   addsitedir     lib       the two dots implies move  up  one directory first  Remember that it all depends on what your current working directory your starting from  If C  Joe Jen Becky   then addsitedir     lib     imports to your path  C  Joe Jen lib C        Joe          Jen                Becky          lib

[python] Python: Best way to add to sys.path relative to the current running script

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