List of 63 Python os Module with Syntax & Examples (Latest)

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8 years ago

List of 63 Python os Module with Syntax & Examples (Latest)

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In this tutorial on Python os Module, we will get closer to the os module and its methods. Moreover, we will study syntax and examples of os Module in Python Programming Language.

So, let’s start Python Module Tutorial

List of 63 Python os Module with Syntax & Examples (Latest)

What is the Python OS Module?

The OS module in Python lets us work with files and directories. We have been using it a lot to get to the Desktop in our examples. But it is much more.

Why should you use the OS Module in Python?

Housekeeper: The OS Module can automatically move the messy files into a folder according to the date and time.
Find a way: The Python OS module tells the script which document folder you are currently running in.
Hidden safe: The code can be secretly written in your computer, which is called the environmental variable. When the script is run, the os module grabs the password.

Let’s discuss the important functions/methods it offers. In case of any doubt, please ask us in the comments.

Let’s check the dir() on this module?

>>> dir(os)

Output

>[‘DirEntry’, ‘F_OK’, ‘MutableMapping’, ‘O_APPEND’, ‘O_BINARY’, ‘O_CREAT’, ‘O_EXCL’, ‘O_NOINHERIT’, ‘O_RANDOM’, ‘O_RDONLY’, ‘O_RDWR’, ‘O_SEQUENTIAL’, ‘O_SHORT_LIVED’, ‘O_TEMPORARY’, ‘O_TEXT’, ‘O_TRUNC’, ‘O_WRONLY’, ‘P_DETACH’, ‘P_NOWAIT’, ‘P_NOWAITO’, ‘P_OVERLAY’, ‘P_WAIT’, ‘PathLike’, ‘R_OK’, ‘SEEK_CUR’, ‘SEEK_END’, ‘SEEK_SET’, ‘TMP_MAX’, ‘W_OK’, ‘X_OK’, ‘_Environ’, ‘__all__’, ‘__builtins__’, ‘__cached__’, ‘__doc__’, ‘__file__’, ‘__loader__’, ‘__name__’, ‘__package__’, ‘__spec__’, ‘_execvpe’, ‘_exists’, ‘_exit’, ‘_fspath’, ‘_get_exports_list’, ‘_putenv’, ‘_unsetenv’, ‘_wrap_close’, ‘abc’, ‘abort’, ‘access’, ‘altsep’, ‘chdir’, ‘chmod’, ‘close’, ‘closerange’, ‘cpu_count’, ‘curdir’, ‘defpath’, ‘device_encoding’, ‘devnull’, ‘dup’, ‘dup2’, ‘environ’, ‘errno’, ‘error’, ‘execl’, ‘execle’, ‘execlp’, ‘execlpe’, ‘execv’, ‘execve’, ‘execvp’, ‘execvpe’, ‘extsep’, ‘fdopen’, ‘fsdecode’, ‘fsencode’, ‘fspath’, ‘fstat’, ‘fsync’, ‘ftruncate’, ‘get_exec_path’, ‘get_handle_inheritable’, ‘get_inheritable’, ‘get_terminal_size’, ‘getcwd’, ‘getcwdb’, ‘getenv’, ‘getlogin’, ‘getpid’, ‘getppid’, ‘isatty’, ‘kill’, ‘linesep’, ‘link’, ‘listdir’, ‘lseek’, ‘lstat’, ‘makedirs’, ‘mkdir’, ‘name’, ‘open’, ‘pardir’, ‘path’, ‘pathsep’, ‘pipe’, ‘popen’, ‘putenv’, ‘read’, ‘readlink’, ‘remove’, ‘removedirs’, ‘rename’, ‘renames’, ‘replace’, ‘rmdir’, ‘scandir’, ‘sep’, ‘set_handle_inheritable’, ‘set_inheritable’, ‘spawnl’, ‘spawnle’, ‘spawnv’, ‘spawnve’, ‘st’, ‘startfile’, ‘stat’, ‘stat_float_times’, ‘stat_result’, ‘statvfs_result’, ‘strerror’, ‘supports_bytes_environ’, ‘supports_dir_fd’, ‘supports_effective_ids’, ‘supports_fd’, ‘supports_follow_symlinks’, ‘symlink’, ‘sys’, ‘system’, ‘terminal_size’, ‘times’, ‘times_result’, ‘truncate’, ‘umask’, ‘uname_result’, ‘unlink’, ‘urandom’, ‘utime’, ‘waitpid’, ‘walk’, ‘write’]

1. access(path,mode) method in Python

This method uses the real uid/gid to test for access to a path. If access is allowed, it returns True.

Else, it returns False. The first argument is the path; the second is the mode.

The mode can take one of four values:

os.F_OK — Found
os.R_OK — Readable
os.W_OK — Writable
os.X_OK — Executable

Now, let’s take an example.

>>> os.chdir('C:\\Users\\lifei\\Desktop')
>>> os.access('Today.txt',os.R_OK)

Output

True

>>> os.access('Today.txt',os.F_OK)

Output

True

>>> os.access('Today.txt',os.W_OK)

Output

True

>>> os.access('Today.txt',os.X_OK)

Output

True

2. chdir(path) method in Python

This Python os module changes the current working directory to the path we specify.

Does this need another example?

>>> os.chdir('C:\\Users\\lifei\\Desktop')

Output

It returns None.

3. chflags(path,flags) method in Python

chflags() sets path flags to the numeric flags. These flags may take a combination(bitwise OR) of the following values:

os.UF_NODUMP – Don’t dump the file
os.UF_IMMUTABLE − You may not change the file
os.UF_APPEND − You may only append to the file
os.UF_NOUNLINK – You may not rename or delete the file
os.UF_OPAQUE − The directory is opaque when we view it through a union stack
os.SF_ARCHIVED – You may archive the file
os.SF_IMMUTABLE – You may not change the file
os.SF_APPEND – You may only append to the file
os.SF_NOUNLINK – You may not rename or delete the file
os.SF_SNAPSHOT − It is a snapshot file

Most flags are such that only the super-user can change them. Also, some flags don’t work on all systems.

Sample usage:

>>> os.chflags('Today.txt',os.SF_NOUNLINK)

4. chmod(path,mode) method in Python

This Python os Module alters the mode of the path to the passed numeric mode.

The mode may be on of the following values(or a bitwise OR combination of them):

stat.S_ISUID − Set user ID on execution
stat.S_ISGID − Set group ID on execution
stat.S_ENFMT – Enforced record locking
stat.S_ISVTX – After execution, save text image
stat.S_IREAD − Read by owner
stat.S_IWRITE − Write by owner
stat.S_IEXEC − Execute by owner
stat.S_IRWXU − Read, write, and execute by owner
stat.S_IRUSR − Read by owner
stat.S_IWUSR − Write by owner
stat.S_IXUSR − Execute by owner
stat.S_IRWXG − Read, write, and execute by group
stat.S_IRGRP − Read by group
stat.S_IWGRP − Write by group
stat.S_IXGRP − Execute by group
stat.S_IRWXO − Read, write, and execute by others
stat.S_IROTH − Read by others
stat.S_IWOTH − Write by others
stat.S_IXOTH − Execute by others

Sample usage:

>>> import stat
>>> os.chmod('Today.txt',stat.S_ISVTX)

This method does not return any value.

5. chroot(path) method in the Python

os.chroot(path) Module alters the current process’s root directory to the given path.

To use this, we need super-user privileges.

Sample usage:

>>> os.chroot("/Photos")

This method returns no value.

6. close(fd) method in the Python

This Python os module closes the associated file with descriptor fd.

>>> fd=os.open('Today.txt',os.O_RDWR)
>>> os.close(fd)

It does not return any value.

7. closerange(fd_low,fd_high) method in the Python

closerange() closes all file descriptors from fd_low to fd_high. Here, fd_low is inclusive, and fd_high is exclusive.

Here, fd_low is the lowest file descriptor to be closed, while fd_high is the highest. This method ignores errors.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> os.write(fd, "Testing")
>>> os.closerange( fd, fd)

This method does not return any value.

8. dup(fd) method in the Python

Python os Module dup(fd) returns a duplicate of the file descriptor fd.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> d_fd = os.dup( fd )
>>> os.write(d_fd, "Testing")
>>> os.closerange( fd, d_fd)

This method returns a duplicate of the file descriptor.

9. dup2(fd,fd2) method in the Python

dup2() duplicates the descriptor fd to fd2. And if necessary, it closes fd2 first.

The interpreter assigns the new file description only when it is available.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> os.write(fd, "Testing")
>>> fd2 = 1000
>>> os.dup2(fd, fd2)
>>> os.lseek(fd2, 0, 0)
>>> str = os.read(fd2, 100)
>>> print(f"Read String is {str}")
>>> os.close( fd )

This method returns a duplicate of the file descriptor.

10. fchdir(fd) method in the Python

fchdir() alters the current working directory to the directory that the file descriptor fd represents.

For this, it is mandatory that the descriptor must refer to an opened directory, and not to an open file.

Sample usage:

>>> os.chdir("/var/www/html" )
>>> print "Current working dir : %s" % os.getcwd()
>>> fd = os.open( "/tmp", os.O_RDONLY )
>>> os.fchdir(fd)
>>> print "Current working dir : %s" % os.getcwd()
>>> os.close( fd )

This method doesn’t return any value.

11. fchmod(fd,mode) method in the Python

This Python os Module alters the file mode of the file, specified by fd, to the numeric mode.

The mode may be one of the following (or an ORed combination of):

stat.S_ISUID − Set user ID on execution
stat.S_ISGID − Set group ID on execution
stat.S_ENFMT − Record locking enforced
stat.S_ISVTX − Save text image after execution
stat.S_IREAD − Read by owner
stat.S_IWRITE − Write by owner
stat.S_IEXEC − Execute by owner
stat.S_IRWXU − Read, write, and execute by owner
stat.S_IRUSR − Read by owner
stat.S_IWUSR − Write by owner
stat.S_IXUSR − Execute by owner
stat.S_IRWXG − Read, write, and execute by group
stat.S_IRGRP − Read by group
stat.S_IWGRP − Write by group
stat.S_IXGRP − Execute by group
stat.S_IRWXO − Read, write, and execute by others
stat.S_IROTH − Read by others
stat.S_IWOTH − Write by others
stat.S_IXOTH − Execute by others

Sample usage:

>>> fd = os.open( "/tmp", os.O_RDONLY )
>>> os.fchmod( fd, stat.S_IXGRP)
>>> os.fchmod(fd, stat.S_IWOTH)
>>> print "Changed mode successfully!!"
>>> os.close( fd )

This method doesn’t return any value.

12. fchown(fd,uid,gid) method in the Python

fchown() alters the owner and the group id of the file specified by fd to the numeric uid and gid.

Setting an id to -1 leaves it unchanged.

Sample usage:

>>> fd = os.open( "/tmp", os.O_RDONLY )
>>> os.fchown( fd, 100, -1)
>>> os.fchown( fd, -1, 50)
>>> print "Changed ownership successfully!!"
>>> os.close( fd )

This method doesn’t return any value.

13. fdatasync(fd) method in the Python

fdatasync() forces writing the file with filedescriptor fd to disk. This, however, doesn’t force update on metadata.

You can do this to flush your buffer.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> os.write(fd, "Testing")
>>> os.fdatasync(fd)
>>> os.lseek(fd, 0, 0)
>>> str = os.read(fd, 100)
>>> print(f"Read String is {str}")
>>> os.close( fd )

This method doesn’t return any value.

14. fdopen(fd[, mode[, bufsize]]) method in the Python

fdopen(), Python os Module returns an open file object. This object is connected to the descriptor fd.

Once you do this, you can perform all defined functions on the file object.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> fo = os.fdopen(fd, "w+")
>>> print (f"Current I/O pointer position {fo.tell()}")
>>> fo.write( "Python is a great language.\nYeah its great!!\n");
>>> os.lseek(fd, 0, 0)
>>> str = os.read(fd, 100)
>>> print (f"Read String is {str}")
>>> print (f"Current I/O pointer position {fo.tell()}")
>>> fo.close()

fdopen() returns an open file object that is connected to the file descriptor.

15. fpathconf(fd, name) method in the Python

fpathconf() returns system configuration information that is relevant to an open file.

This is quite similar to the Unix system call fpathconf(). It also accepts similar arguments.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> print (f"{os.pathconf_names}")
>>> no = os.fpathconf(fd, 'PC_LINK_MAX')
>>> print (f"Maximum number of links to the file: {no}")
>>> no = os.fpathconf(fd, 'PC_NAME_MAX')
>>> print (f"Maximum length of a filename :{no}")
>>> os.close( fd)

fpathconf() returns system configuration that is relevant to an open file.

16. fstat(fd) method in Python

Python os Module fstat() returns information about the file pertaining to the fd.

Let’s take a look at the structure fstat() returns:

st_dev − ID of device containing file
st_ino − inode number
st_mode – protection
st_nlink − number of hard links
st_uid − user ID of owner
st_gid − group ID of owner
st_rdev − device ID (if special file)
st_size − total size, in bytes
st_blksize − blocksize for filesystem I/O
st_blocks − number of blocks allocated
st_atime − time of last access
st_mtime − time of last modification
st_ctime − time of last status change

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> info = os.fstat(fd)
>>> print (f"File Info: {info}")
>>> print (f"UID of the file: {info.st_uid}")
>>> print (f"GID of the file: {info.st_gid}")
>>> os.close( fd)

fstat() returns information about the file linked with the fd.

17. fstatvfs(fd) method in Python

This Python os module returns information pertaining to the file system containing the file linked with file descriptor fd.

This is the structure it returns:

f_bsize − file system block size
f_frsize − fragment size
f_blocks − size of fs in f_frsize units
f_bfree − free blocks
f_bavail − free blocks for non-root
f_files – inodes
f_ffree − free inodes
f_favail − free inodes for non-root
f_fsid − file system ID
f_flag − mount flags
f_namemax − maximum filename length

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> info = os.fstatvfs(fd)
>>> print(f"File Info: {info}")
>>> print(f"Maximum filename length: {info.f_namemax}")
>>> print (f"Free blocks: {info.f_bfree}")
>>> os.close( fd)

fstatvfs() returns information about the file system containing the file linked.

18. fsync(fd) method in Python

This Python os Module forces write on the file liknked to the descriptor fd to disk.

Beginning with a Python file object f, first execute f.flush(), then perform os.fsync(f.fileno()).

Do this to ensure all internal buffers linked to f are written to the disk.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> os.write(fd, "Testing")
>>> os.fsync(fd)
>>> os.lseek(fd, 0, 0)
>>> str = os.read(fd, 100)
>>> print("Read String is: {str} ")
>>> os.close( fd )

fsync() doesn’t return any value.

19. ftruncate(fd,length) method in Python

ftruncate() truncates the file linked to the descriptor fd, so it holds at most length bytes in size.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> os.write(fd, "Testing")
>>> os.ftruncate(fd, 10)
>>> os.lseek(fd, 0, 0)
>>> str = os.read(fd, 100)
>>> print("Read String is: {str}”)
>>> os.close( fd )

ftruncate() doesn’t return any value.

20. getcwd() method in Python

getcwd() Python os Module returns the current working directory of a process.

Sample usage:

>>> os.getcwd()

Output

‘C:\\Users\\lifei\\Desktop’

21. getcwdu() method in Python

getcwdu() returns a Unicode object that represents the current working directory.

Sample usage:

>>> os.chdir("/var/www/html" )
>>> print(f"Current working dir: {os.getcwdu()}")
>>> fd = os.open( "/tmp", os.O_RDONLY )
>>> os.fchdir(fd)
>>> print(f"Current working dir: {os.getcwdu()}”)
>>> os.close( fd )

22. isatty(fd) method in Python

isatty()returns True if the descriptor fd is open, and is connected to a tty(-like) device. Otherwise, it returns False.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> os.write(fd, "Testing")
>>> ret = os.isatty(fd)
>>> print(f"Returned value is: {ret}")
>>> os.close( fd )

23. lchflags(path,flags) method in Python

This Python os Module sets path flags to the numeric flags. Unlike chflags(), ut doesn’t follow symbolic links.

The flags may be one of the following values, or a bitwise OR combination of:

UF_NODUMP − Do not dump the file
UF_IMMUTABLE − The file may not be changed
UF_APPEND − The file may only be appended to
UF_NOUNLINK − The file may not be renamed or deleted
UF_OPAQUE − The directory is opaque when viewed through a union stack
SF_ARCHIVED − The file may be archived
SF_IMMUTABLE − The file may not be changed
SF_APPEND − The file may only be appended to
SF_NOUNLINK − The file may not be renamed or deleted
SF_SNAPSHOT − The file is a snapshot file.

Sample usage:

>>> path = "/var/www/html/Today.txt"
>>> fd = os.open( path, os.O_RDWR)
>>> os.close( fd )
>>> ret = os.lchflags(path, os.UF_IMMUTABLE )

lchflags() doesn’t return a value.

24. lchmod(path,mode) method in Python

lchmod() Python os Module ters the path mode to the numeric mode. If the path is a symlink, it affects the symlink, not the target.

The mode may be one of the following values, or a bitwise OR combination of:

stat.S_ISUID − Set user ID on execution
stat.S_ISGID − Set group ID on execution
stat.S_ENFMT − Record locking enforced
stat.S_ISVTX − Save text image after execution
stat.S_IREAD − Read by owner
stat.S_IWRITE − Write by owner
stat.S_IEXEC − Execute by owner
stat.S_IRWXU − Read, write, and execute by owner
stat.S_IRUSR − Read by owner
stat.S_IWUSR − Write by owner
stat.S_IXUSR − Execute by owner
stat.S_IRWXG − Read, write, and execute by group
stat.S_IRGRP − Read by group
stat.S_IWGRP − Write by group
stat.S_IXGRP − Execute by group
stat.S_IRWXO − Read, write, and execute by others
stat.S_IROTH − Read by others
stat.S_IWOTH − Write by others
stat.S_IXOTH − Execute by others

Sample usage:

>>> path = "/var/www/html/Today.txt"
>>> fd = os.open( path, os.O_RDWR )
>>> os.close( fd )
>>> os.lchmod( path, stat.S_IXGRP)
>>> os.lchmod("/tmp/Today.txt", stat.S_IWOTH)

lchmod() doesn’t return any value.

25. lchown(path,uid,gid) method in Python

Python os Module lchown() alters the owner and group ID of the path to the numeric uid and gid.

It doesn’t follow symbolic links. Setting an id to -1 leaves it unchanged.

Sample usage:

>>> path = "/var/www/html/Today.txt"
>>> fd = os.open( path, os.O_RDWR)
>>> os.close( fd )
>>> os.lchown( path, 500, -1)
>>> os.lchown( path, -1, 500)

lchown() doesn’t return any value.

26. link(src,dst) method in Python

link() will create a hard link that points to an src named dst.

You can do this when you want to create a copy of an existing file.

Sample usage:

>>> path = "/var/www/html/Today.txt"
>>> fd = os.open( path, os.O_RDWR )
>>> os.close( fd )
>>> dst = "/tmp/Today.txt"
>>> os.link( path, dst)

lilnk() doesn’t return any value.

27. The listdir(path) method in Python

listdir() will return a list holding the names of the entries in the directory at the path.

This list is in an arbitrary order, and it excludes special entries ‘.’ and ‘..’, even if they exist in the directory.

Sample usage:

>>> path = "/var/www/html/"
>>> dirs = os.listdir( path )
>>> for file in dirs:
print(file)

28. lseek(fd,pos,how) method in Python

lseek() will set the current position of the descriptor fd to the specified position pos. ‘how’ modifies it.

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> os.write(fd, "This is test")
>>> os.fsync(fd)
>>> os.lseek(fd, 0, 0)
>>> str = os.read(fd, 100)
>>> print(f"Read String is: {str}")
>>> os.close( fd )

lseek() doesn’t return any value.

29. lstat(path) method in Python

Like fstat(), lstat() returns information about a file, but does not follow symbolic links.

lstat is an alias for fstat() on those platforms that do not support symbolic links, for instance, Windows.

It returns the following structure:

st_dev − ID of device containing file
st_ino − inode number
st_mode – protection
st_nlink − number of hard links
st_uid − user ID of owner
st_gid − group ID of owner
st_rdev − device ID (if special file)
st_size − total size, in bytes
st_blksize − blocksize for filesystem I/O
st_blocks − number of blocks allocated
st_atime − time of last access
st_mtime − time of last modification
st_ctime − time of last status change

Sample usage:

>>> path = "/var/www/html/Today.txt"
>>> fd = os.open( path, os.O_RDWR)
>>> os.close( fd )
>>> info = os.lstat(path)
>>> print(f"File Info: {info}")
>>> print(f"UID of the file: {info.st_uid}")
>>> print(f"GID of the file: {info.st_gid}")

30. major(device) method in Python

major() takes a raw device number, and extracts the device major number (usually the st_dev or st_rdev field from stat).

Sample usage:

>>> path = "/var/www/html/Today.txt"
>>> info = os.lstat(path)
>>> major_dnum = os.major(info.st_dev)
>>> minor_dnum = os.minor(info.st_dev)
>>> print(f"Major Device Number: {major_dnum}")
>>> print(f"Minor Device Number: {minor_dnum}")

major() returns the device major number.

31. makedev(major,minor) method in Python

This Python os Module takes the minor and major device numbers and creates a raw device number.

Sample usage:

>>> path = "/var/www/html/Today.txt"
>>> info = os.lstat(path)
>>> major_dnum = os.major(info.st_dev)
>>> minor_dnum = os.minor(info.st_dev)
>>> print(f"Major Device Number: {major_dnum}")
>>> print(f"Minor Device Number: {minor_dnum}")
>>> dev_num = os.makedev(major_dnum, minor_dnum)
>>> print(f"Device Number: {dev_num}")

makedev() returns the device number.

32. makedirs(path[, mode]) method in Python

makedirs() creates a directory recursively. This way, it is like mkdir().

However, it mandates that all intermediate-level directories contain the leaf directory.

Sample usage:

>>> path = "/tmp/home/monthly/daily"
>>> os.makedirs( path, 0755 )

33. minor(device) method in Python

Python os Module minor() will take a raw device number, and extract the device’s minor (usually the st_dev or st_rdev field from stat).

Sample usage:

>>> path = "/var/www/html/Today.txt"
>>> info = os.lstat(path)
>>> major_dnum = os.major(info.st_dev)
>>> minor_dnum = os.minor(info.st_dev)
>>> print(f"Major Device Number: {major_dnum}")
>>> print(f"Minor Device Number: {minor_dnum}")

minor() returns the device’s minor number.

34. mkdir(path[, mode]) method in Python

mkdir() Python os Module creates a directory ‘path’ with the numeric mode ‘mode’. Some systems ignore mode.

But where used, it masks out the current umask value first.
Default mode=0777 (octal).

Sample usage:

>>> path = "/tmp/home/monthly/daily/hourly"
>>> os.mkdir( path, 0755 )

mkdir() doesn’t return any value.

35. mkfifo(path[, mode]) method in Python

mkfifo() creates a FIFO named ‘path’ with the specified numeric mode. It masks out the current umask value first.
Default mode=0666 (octal).

Sample usage:

>>> path = "/tmp/hourly"
>>> os.mkfifo( path, 0644 )

mkfifo() doesn’t return any value.

36. mknod(filename[, mode=0600, device]) method in Python

This Python os Module will create a filesystem node named ‘filename’. This can be a file, a device-special file, or a named pipe.

Sample usage:

>>> filename = '/tmp/tmpfile'
>>> mode = 0600|stat.S_IRUSR
>>> os.mknod(filename, mode)

mknod() doesn’t return any value.

37. open(file, flags[, mode]) method in Python

open() will open the file ‘file’, and will set flags based on the specified flags.

It possibly sets its mode according to the specified mode. It also masks out the current umask value first.

Default mode=0777 (octal).

The flags may take one of these values, or a bitwise-OR combination of these:

os.O_RDONLY − open for reading only
os.O_WRONLY − open for writing only
os.O_RDWR − open for reading and writing
os.O_NONBLOCK − do not block on open
os.O_APPEND − append on each write
os.O_CREAT − create file if it does not exist
os.O_TRUNC − truncate size to 0
os.O_EXCL − error if create and file exists
os.O_SHLOCK − atomically obtain a shared lock
os.O_EXLOCK − atomically obtain an exclusive lock
os.O_DIRECT − eliminate or reduce cache effects
os.O_FSYNC − synchronous writes
os.O_NOFOLLOW − do not follow symlinks

Sample usage:

>>> fd = os.open( "Today.txt", os.O_RDWR)
>>> os.write(fd, "This is test")
>>> os.close( fd )

open() returns the descriptor for the file we opened.

38. openpty() method in Python

Python os Module openpty() opens a pseudo-terminal pair.

Then, it returns a pair of descriptors- master & slave- for the pty & the tty, respectively.

Sample usage:

>>> m,s = os.openpty()
>>> print(m)
>>> print(s)
>>> s = os.ttyname(s)
>>> print(m)
>>> print(s)

39. pathconf(path,name) method in Python

Python os Module pathconf() returns system configuration information pertaining to a named file.

Sample usage:

>>> print(f"{os.pathconf_names}" )
>>> no = os.pathconf('a2.py', 'PC_NAME_MAX')
>>> print(f"Maximum length of a filename: {no}")
>>> no = os.pathconf('a2.py', 'PC_FILESIZEBITS')
>>> print(f"file size in bits: {no}")

40. pipe() method in Python

pipe() creates a pipe. Then, it returns a pair of descriptors- r & w- for reading and writing.

Sample usage:

>>> os.pipe()

Output

(3, 4)

41. popen(command[, mode[, bufsize]]) method in Python

This Python os Module popen() will open a pipe to, or from, the command specified. It returns an open file object that is connected to the pipe.

We can read or write to this object depending on whether the mode is ‘r’ (default) or ‘w’. The bufsize argument means the same as in the open() function.

Sample usage:

>>> a = 'mkdir nwdir'
>>> b = os.popen(a,'r',1)

42. read(fd,n) method in Python

read() Python os Module will let us read at most n bytes from the descriptor fd. It returns a string holding the bytes we just read.

And if it reaches the end of the file, it returns an empty string.

Sample usage:

>>> fd = os.open("f1.txt",os.O_RDWR)
>>> ret = os.read(fd,12)
>>> print(ret)
>>> os.close(fd)

43. readlink(path) method in Python

Python os Module readlink() will return a string denoting the path to which the symbolic link points. It may return a relative or an absolute pathname.

Sample usage:

>>> src = '/usr/bin/python'
>>> dst = '/tmp/python'
>>> os.symlink(src, dst)
>>> path = os.readlink( dst )
>>> print(path)

44. remove(path) method in Python

remove() removes the specified file path. If that path is a directory, it raises an OSError.

Sample usage:

>>> print(f"The dir is: {os.listdir(os.getcwd())}")
>>> os.remove("aa.txt")
>>> print(f"The dir after removal of path: {os.listdir(os.getcwd())}")

remove() doesn’t return any value.

45. removedirs(path) method in Python

This Python os Module will remove directories recursively.

And if we successfully remove the leaf directory, it attempts to successively remove every parent directory displayed in that path.

Sample usage:

>>> print(f"The dir is: {os.listdir(os.getcwd())}")
>>> os.removedirs("/tutorialsdir")
>>> print(f"The dir after removal is: {os.listdir(os.getcwd())}")

removedirs() doesn’t return any value.

46. rename(src,dst) method in Python

rename() renames a file or directory. If the destination is a file or a directory that already exists, it raises an OSError.

Sample usage:

>>> print(f"The dir is: {os.listdir(os.getcwd())}”)
>>> os.rename("tutorialsdir","tutorialsdirectory")
>>> print(“Successfully renamed”)
>>> print(f"The dir is: {os.listdir(os.getcwd())}")

rename() doesn’t return any value.

47. renames(old,new) method in Python

renames() Python os Module renames directories and files recursively.

It is like os.rename(), but it also moves a file to a directory, or a whole tree of directories, that do not already exist.

Sample usage:

>>> print("Current directory is: { os.getcwd()}")
>>> print("The dir is: { os.listdir(os.getcwd())}")
>>> os.renames("aa1.txt","newdir/aanew.txt")
>>> print("Successfully renamed”)
>>> print(f"The dir is: {os.listdir(os.getcwd())}")

renames() does not return any value.

48. rmdir(path) method in Python

Python os Module rmdir() removes the directory path specified. If the directory isn’t empty, however, it raises an OSError.

Sample usage:

>>> print(f"the dir is: { os.listdir(os.getcwd())}")
>>> os.rmdir("mydir")
>>> print(f"the dir is: { os.listdir(os.getcwd())}"

rmdir() doesn’t return any value.

49. stat(path) method in Python

This Python os Module performs a stat system call on the specified path.
These are the members of the stat structure:

st_mode − protection bits
st_ino − inode number
st_dev − device
st_nlink − number of hard links
st_uid − user ID of the owner
st_gid − group ID of owner
st_size − size of file, in bytes
st_atime − time of most recent access
st_mtime − time of most recent content modification
st_ctime − time of most recent metadata change.

Sample usage:

>>> statinfo = os.stat('a2.py')
>>> print(statinfo)

50. stat_float_times([newvalue]) method in Python

stat_float_times() Python os Module decides whether stat_result denotes time stamps as float objects.

Sample usage:

>>> import os, sys
>>> statinfo = os.stat('a2.py')
>>> print(statinfo)
>>> statinfo = os.stat_float_times()
>>> print(statinfo)

51. statvfs(path) method in Python

Python os Module statvfs() executes a statvfs system call on the specified path.

The structure has the following members:

f_bsize − preferred file system block size
f_frsize − fundamental file system block size
f_blocks − total number of blocks in the filesystem
f_bfree − total number of free blocks
f_bavail − free blocks available to non-super user
f_files − total number of file nodes
f_ffree − total number of free file nodes
f_favail − free nodes available to non-super user
f_flag − system dependent
f_namemax − maximum file name length

Sample usage:

>>> stinfo = os.statvfs('a1.py')
>>> print(stinfo)

52. symlink(src,dst) method in Python

symlink() composes a symbolic link dst that points to the source.

Sample usage:

>>>src = '/usr/bin/python'
>>> dst = '/tmp/python'
>>> os.symlink(src, dst)

symlink() returns no value.

53. tcgetpgrp(fd) method in Python

This Python os Module returns the process group linked to the terminal specified by fd, which is an open file descriptor, and is returned by os.open().

Sample usage:

>>> print(f"Current working dir : { os.getcwd()}")
>>> fd = os.open("/dev/tty",os.O_RDONLY)
>>> f = os.tcgetpgrp(fd)
>>> print(f"the process group associated is: {f}")
>>> os.close(fd)

tcgetpgrp() returns the process group.

54. tcsetpgrp(fd, pg) method in Python

Python os Module tcsetpgrp() sets the process group linked to the terminal specified by fd, which is an open file descriptor, and is returned by os.open(), to pg.

Sample usage:

>>> print(f"Current working dir : { os.getcwd()}")
>>> fd = os.open("/dev/tty",os.O_RDONLY)
>>> f = os.tcgetpgrp(fd)
>>> print(f"the process group associated is: {f}")
>>> os.tcsetpgrp(fd,2672)
>>> print("done")
>>> os.close(fd)

tcsetpgrp() returns no value.

55. tempnam([dir[, prefix]]) method in Python

tempnam() Python os Module returns a unique path name reasonable enough to create a temporary file.

Sample usage:

>>> tmpfn = os.tempnam('/tmp/tutorialsdir,'tuts1')

tempnam() returns a unique path.

56. tmpfile() method in Python

tmpfile() will return a new temporary file object, opening it in update mode (w+b).

This file has zero directory entries linked to it, and will automatically delete when no descriptors are available.

Sample usage:

>>> tmpfile = os.tmpfile()
>>> tmpfile.write('Temporary newfile is here.....')
>>> tmpfile.seek(0)
>>> print(tmpfile.read())
>>> tmpfile.close()

57. tmpnam() method in Python

tmpnam() will return a unique path name reasonable enough to create a temporary file.

Sample usage:

>>> tmpfn = os.tmpnam()
>>> print(f"This is the unique path: {tmpfn}")

58. ttyname(fd) method in Python

ttyname() Python os Module will return a string that denotes the terminal device linked to the descriptor fd.

If it isn’t linked to a terminal device, it raises an exception.

Sample usage:

>>> print(f"Current working dir : { os.getcwd()}")
>>> fd = os.open("/dev/tty",os.O_RDONLY)
>>> p = os.ttyname(fd)
>>> print(f"the terminal device associated is: {p}")
>>> os.close(fd)

ttyname() returns a string that denotes the terminal device.

59. unlink(path) method in Python

This Python os Module will remove the specified file path. If it is a directory, it raises an OSError.

Sample usage:

>>> print(f"The dir is: { os.listdir(os.getcwd())}")
>>> os.unlink("aa.txt")
>>> print(f"The dir after removal of path : { os.listdir(os.getcwd())}")

unlink() doesn’t return any value.

60. utime(path,times) method in Python

Python os Module utime() sets the access and modified times of the file at the specified path.

Sample usage:

>>> stinfo = os.stat('a2.py')
>>> print(stinfo)
>>> print(f"access time of a2.py: { stinfo.st_atime }")
>>> print(f"modified time of a2.py: { stinfo.st_mtime }")
>>> os.utime("a2.py",(1330712280, 1330712292))

utime() returns no value.

61. walk(top[, topdown=True[, onerror=None[, followlinks=False]]])

walk() creates file names in a directory tree. It does so by walking the tree either bottom-up or top-down.

It has the following parameters:

top − Each directory rooted at directory
topdown − If topdown is True, or not specified, it scans directories top-down.
onerror − This may show an error to continue with the walk, or may raise an exception to abort the walk.
followlinks − This will visit directories that symlinks points to, that is, if set to true.

Sample usage:

>>> for root, dirs, files in os.walk(".", topdown=False):

Output

for name in files:
print(os.path.join(root, name))
for name in dirs:
print(os.path.join(root, name))

62. write(fd,str) method in Python

This Python os Module will write the specified string to descriptor fd. It returns the number of bytes that it actually wrote.

Sample usage:

>>> fd = os.open("f1.txt",os.O_RDWR|os.CREAT)
>>> ret = os.write(fd,"This is test")
>>> print(f"the number of bytes written: {ret}")
>>> print("written successfully")
>>> os.close(fd)

So, this was all about the Python os Module. Hope you like our explanation.

Python Interview Questions on OS Modules

What is the OS Module in Python?
How to open an OS Module in Python?
What is the use of the OS Module in Python?
What is the OS Path Module in Python?
What is the import OS SYS in Python?

Conclusion

Hence, we cover all the Python os module. This will allow you to work your way around the directories without any problem.