mkdir -p functionality in Python [duplicate]

Question

Is there a way to get functionality similar to mkdir -p on the shell from within Python. I am looking for a solution other than a system call. I am sure the code is less than 20 lines, and I am wondering if someone has already written it?

Tumbleweed

How to achieve "mkdir -p /home/Documents/Folder/{Subfolder1,Subfolder2}" equivalent in os.command ? It's creating a folder as {Subfolder1,Subfolder2} instead of 2 different folders – Leavelle

What is different between makedirs and mkdir of os? – Extrapolate

That {Subfolder1,Subfolder2} syntax is a feature of bash (and some other shells), not mkdir -p. e.g. echo prefix-{Subfolder1,Subfolder2} will show "prefix-Subfolder1 prefix-Subfolder2". – Fluent

Answer 1

For Python ≥ 3.5, use pathlib.Path.mkdir:

import pathlib
pathlib.Path("/tmp/path/to/desired/directory").mkdir(parents=True, exist_ok=True)

The exist_ok parameter was added in Python 3.5.

---

For Python ≥ 3.2, os.makedirs has an optional third argument exist_ok that, when True, enables the mkdir -p functionality—unless mode is provided and the existing directory has different permissions than the intended ones; in that case, OSError is raised as previously:

import os
os.makedirs("/tmp/path/to/desired/directory", exist_ok=True)

---

For even older versions of Python, you can use os.makedirs and ignore the error:

import errno    
import os

def mkdir_p(path):
    try:
        os.makedirs(path)
    except OSError as exc:  # Python ≥ 2.5
        if exc.errno == errno.EEXIST and os.path.isdir(path):
            pass
        # possibly handle other errno cases here, otherwise finally:
        else:
            raise

Wentzel

This version also avoids races as the file system might change between the os.path.exist() and os.makedirs() – Warfield

In the spirit of micro-improving something lots of people will copy+paste: how about replacing == with != and removing the pass/else :-) – Reuven

@Will: I prefer this method (else: raise), because this way is easier to add handling of more exc.errno cases (elif exc.errno == errno.EACCES: etc) – Wentzel

@JohnnyLambada you mean python < 3.0 ? – Maighdlin

@JensTimmerman: it's obligatory for Python ≤ 2.5 and optional (but still valid) for 2.5 < Python < 3. – Wentzel

this is clearly a design bug in os.makedirs(): zero and one should not be handled in a special way. ah well, unix made the same mistake for many tools – Irreconcilable

@Sam there is exist_ok parameter – Planck

@SetJmp: it requires at least 2 calls: stat() to check that the parent dir exists and mkdir() to create the directory. – Planck

This appears to fail if the last portion of path is a file, as exc.errno equals errno.EEXIST and so everything seems ok, but actually using the directory later will obviously fail. – Certifiable

What about distutils.dir_util.mkpath? It's pretty simple as mkpath('./foo/bar') – Independence

Optimize exception handling? except OSError as exc: if exc.errno != errno.EEXIST or not os.path.isdir(path): raise – Costrel

@auraham, mkpath has some unexpected behavior due to undocumented caching that may cause problems if you try to use it exactly like mkdir -p: bugs.python.org/issue10948. – Hardison

I actually receive an UnicodeDecodeError if the path already exists. Is this a bug? Python (2.7) is probably passing the string received from the OS without checking. It probably contains some non-ascii characters, in which case the above exception fails: UnicodeDecodeError: 'ascii' codec can't decode byte 0xe3 in position 13: ordinal not in range(128) – Drugget

any explanation of what is going on in the except .... raise part? – Taunt

@lambacck: "Other implementations ... have a potential race condition bug." Since you can't lock the file system, all implementations, including this one, have a race condition when considered as part of the code that calls it: another process could delete the directory between you creating it and putting something in it. I think it's best not to worry about such things in the lower level code but have a try block around the higher-level code block to catch them. That's closer to the Python spirit of asking for forgiveness. – Ecclesiastes

But this one solves the very common race condition of two threads trying to create the same directory at the exact same time. The not os.path.exists has a high chance of calling the os.makedirs at the same time. – Charpoy

To protect against race conditions, you can install IPython and use IPython.utils.path.ensure_dir_exists() – Untruth

Wish they'd named this mkdirs in accordance with mkdir and not suddenly makedirs ... – Secondrate

Is pathlib preferable to OS? Why? – Keelia

Answer 2

In Python >=3.2, that's

os.makedirs(path, exist_ok=True)

In earlier versions, use @tzot's answer.

Several

This worked for me. To understand why, see documentation here (search for "makedirs"): docs.python.org/3/library/os.html – Breadfruit

Answer 3

This is easier than trapping the exception:

import os
if not os.path.exists(...):
    os.makedirs(...)

Disclaimer This approach requires two system calls which is more susceptible to race conditions under certain environments/conditions. If you're writing something more sophisticated than a simple throwaway script running in a controlled environment, you're better off going with the accepted answer that requires only one system call.

UPDATE 2012-07-27

I'm tempted to delete this answer, but I think there's value in the comment thread below. As such, I'm converting it to a wiki.

Bullfrog

This way, you make it less probable but not impossible that makedirs will fail, in all multitasking operating systems. It's like saying "256 chars should be enough for any path created". – Wentzel

I like this solution, though a friend pointed out that the longer exception based solution would only need one file system call. So on a really high latency corporate NFS server, I would want to go with the exception based approach. – Tumbleweed

@setjmp I agree. You probably don't want to use this approach in an enterprise setting, but would work just fine for some simple scripting. I inferred that is what you were looking for from the way you phrased your question. – Bullfrog

consider what happens in this code if the path doesn't exist, but you don't have permission to create the folder. You still get an exception. – Armure

@Asa Of course. And mkdir -p would complain about that too. Did I miss your point? – Bullfrog

@jholloway7: based on the requirements ("mkdir -p"-like functionality) Asa's comment is unnecessary. However, I would like to know whether you do acknowledge that it's possible that the directory can be non-existent when .exists is called, and existent when .makedirs is called. – Wentzel

@TZ Yes, I certainly acknowledge that. Again, without complete specifications from the original poster, my assumption was that he/she wanted a solution that could be used to create a directory tree if not already existing in a simple script, not a HA enterprisey production solution with SLAs. – Bullfrog

@Asa That's what exceptions are for, something unexpected went wrong. If you don't have permissions the exception bubbles all the way up and you notice to fix the permissions. As it should be. – Dried

adding simplicity to tzot's original solution: def mkdir_p(path): if not os.path.isdir(path): os.makedirs(path); – Fraze

@RyanJensen The beef everyone has with my answer is that it makes two system calls and is not a single atomic operation. Yours has the same flaw, so just be mindful that it's only usable in very constrained applications and not the best idea for a general purpose solution – Bullfrog

Answer 4

Recently, I found this distutils.dir_util.mkpath:

In [17]: from distutils.dir_util import mkpath

In [18]: mkpath('./foo/bar')
Out[18]: ['foo', 'foo/bar']

Independence

Beware, mkpath() caches the directory so that you can't re-mkpath() a directory that has been removed with a different method: bugs.python.org/issue10948. – Hardison

@Hardison Moreover the method is intended to be private, in case anyone else is tempted to read the bug report to see if it's been 'fixed' (it's not a bug). – Tandi

@MauroBaraldi the point is that if you create a directory with this method, it gets deleted and you try to create it again using this method from the same program, it won't work. Don't use this. – Tapioca

Answer 5

With Pathlib from python3 standard library:

Path(mypath).mkdir(parents=True, exist_ok=True)

If parents is true, any missing parents of this path are created as needed; they are created with the default permissions without taking mode into account (mimicking the POSIX mkdir -p command). If exist_ok is false (the default), an FileExistsError is raised if the target directory already exists.

If exist_ok is true, FileExistsError exceptions will be ignored (same behavior as the POSIX mkdir -p command), but only if the last path component is not an existing non-directory file.

Changed in version 3.5: The exist_ok parameter was added.

Gyro

For python < 3.5 you can use pathlib2. pip install pathlib2; from pathlib2 import Path – Solution

I don't like this method - prefer the os.mkdir option. SIlent continue if you delete and recreate folders in conjunction with shutil.rmtree - leaving a lock. os version gives access denied -and abends early rather than later. Setting up a folder of results from a huge conversion which would not be able to output results – Lashaunda

Answer 6

mkdir -p gives you an error if the file already exists:

$ touch /tmp/foo
$ mkdir -p /tmp/foo
mkdir: cannot create directory `/tmp/foo': File exists

So a refinement to the previous suggestions would be to re-raise the exception if os.path.isdir returns False (when checking for errno.EEXIST).

(Update) See also this highly similar question; I agree with the accepted answer (and caveats) except I would recommend os.path.isdir instead of os.path.exists.

(Update) Per a suggestion in the comments, the full function would look like:

import os
def mkdirp(directory):
    if not os.path.isdir(directory):
        os.makedirs(directory) 

Chelsea

You are absolutely correct about this case; however, the program should catch exceptions later on e.g. when trying to open("/tmp/foo/a_file", "w"), so I don't think an update is necessary. You could update your answer with Python code instead, and watch it being upvoted ;) – Wentzel

In a lot of cases that would probably be fine. In general, though, I would prefer the code to fail as early as possible so it's clear what really caused the problem. – Chelsea

If it already exists AS A DIRECTORY, mkdir -p does not error. It does error if you ask it to create a directory, and a FILE by that name already exists. – Shikoku

@FrankKlotz that's why I'm calling os.path.isdir not os.path.exists – Chelsea

−1 because the only part of this answer that actually answers the question (the last code block) answers it incorrectly and also duplicates other answers. – Streamlet

If you use pathlib, then Path("/tmp/my/file").mkdir(parents=True, exist_ok=True) it behaves the same way too. It'll raise a FileExistsError – Tapioca

Answer 7

As mentioned in the other solutions, we want to be able to hit the file system once while mimicking the behaviour of mkdir -p. I don't think that this is possible to do, but we should get as close as possible.

Code first, explanation later:

import os
import errno

def mkdir_p(path):
    """ 'mkdir -p' in Python """
    try:
        os.makedirs(path)
    except OSError as exc:  # Python >2.5
        if exc.errno == errno.EEXIST and os.path.isdir(path):
            pass
        else:
            raise

As the comments to @tzot's answer indicate there are problems with checking whether you can create a directory before you actually create it: you can't tell whether someone has changed the file system in the meantime. That also fits in with Python's style of asking for forgiveness, not permission.

So the first thing we should do is try to make the directory, then if it goes wrong, work out why.

As Jacob Gabrielson points out, one of the cases we must look for is the case where a file already exists where we are trying to put the directory.

With mkdir -p:

$ touch /tmp/foo
$ mkdir -p /tmp/foo
mkdir: cannot create directory '/tmp/foo': File exists

The analogous behaviour in Python would be to raise an exception.

So we have to work out if this was the case. Unfortunately, we can't. We get the same error message back from makedirs whether a directory exists (good) or a file exists preventing the creation of the directory (bad).

The only way to work out what happened is to inspect the file system again to see if there is a directory there. If there is, then return silently, otherwise raise the exception.

The only problem is that the file system may be in a different state now than when makedirs was called. eg: a file existed causing makedirs to fail, but now a directory is in its place. That doesn't really matter that much, because the the function will only exit silently without raising an exception when at the time of the last file system call the directory existed.

Bohemia

Or just: os.makedirs(path, exist_ok=True) – Alerion

Answer 8

I think Asa's answer is essentially correct, but you could extend it a little to act more like mkdir -p, either:

import os

def mkdir_path(path):
    if not os.access(path, os.F_OK):
        os.mkdirs(path)

or

import os
import errno

def mkdir_path(path):
    try:
        os.mkdirs(path)
    except os.error, e:
        if e.errno != errno.EEXIST:
            raise

These both handle the case where the path already exists silently but let other errors bubble up.

Bookrest

On Python 2.7.6 ... [GCC 4.8.2] on linux2, at least, it seems that it should be os.mkdir, not os.mkdirs. – Anthropo

the first option is susceptible to race conditions (at one instant, the dir is not there, so we proceed to create it but in the middle something else creates it and boom!) second option is the way to go in Python 2 – Couture

Answer 9

Function declaration;

import os
def mkdir_p(filename):

    try:
        folder=os.path.dirname(filename)  
        if not os.path.exists(folder):  
            os.makedirs(folder)
        return True
    except:
        return False

usage :

filename = "./download/80c16ee665c8/upload/backup/mysql/2014-12-22/adclient_sql_2014-12-22-13-38.sql.gz"

if (mkdir_p(filename):
    print "Created dir :%s" % (os.path.dirname(filename))

Satang

Answer 10

import os
import tempfile

path = tempfile.mktemp(dir=path)
os.makedirs(path)
os.rmdir(path)

Claypan

Answer 11

I've had success with the following personally, but my function should probably be called something like 'ensure this directory exists':

def mkdirRecursive(dirpath):
    import os
    if os.path.isdir(dirpath): return

    h,t = os.path.split(dirpath) # head/tail
    if not os.path.isdir(h):
        mkdirRecursive(h)

    os.mkdir(join(h,t))
# end mkdirRecursive

Dallapiccola

this is a nice answer for 2.7, seems cleaner than trapping an error – Anthozoan

fails if part of the tree already exists though, so here's a fix:- import os; from os.path import join as join_paths def mk_dir_recursive(dir_path): if os.path.isdir(dir_path): return h, t = os.path.split(dir_path) # head/tail if not os.path.isdir(h): mk_dir_recursive(h) new_path = join_paths(h, t) if not os.path.isdir(new_path): os.mkdir(new_path) – Anthozoan

Answer 12

import os
from os.path import join as join_paths

def mk_dir_recursive(dir_path):

    if os.path.isdir(dir_path):
        return
    h, t = os.path.split(dir_path)  # head/tail
    if not os.path.isdir(h):
        mk_dir_recursive(h)

    new_path = join_paths(h, t)
    if not os.path.isdir(new_path):
        os.mkdir(new_path)

based on @Dave C's answer but with a bug fixed where part of the tree already exists

Anthozoan