Directory Navigation

I LOVE DOING THIS :)

Directory details ?

• Methods for traversing directories

• Listing files and thier information

• Creating and Deleting directories + files

• Test to check if something is a file or directory

Inorder to perform all this, we'll have to import the os module

>>> import os
>>> os.getcwd()        // Prints Current Working Directory
/root/
>>>
>>> os.listdir("/")    // Lists the root directory within a list

Let's quickly write a program to check if a file is actually a file or a directory

#!/opt/python3

for i in os.listdir("."):
	if os.path.isfile(i):
		print(i + "is a file")
		print("-----------------")

	elif os.path.isdir(i):
		print(i + "is a directory")
		print("-----------------")

• os.path.isfile() and os.path.isdir() checks for the file or the directory

So, now how do we search for specific kind of files ? How do we grep them ?

>>> for i in glob.glob(os.path.join(".", "*.py")):
...    print(i)
...
~./file_desc.py
~./navigation.py
~./source.py

glob — Unix style pathname pattern expansionPython documentation

Have a read !

Exercise Question

• Create a program which takes the path of directory as input and from that directory it checks all the files within it and makes sure if it's really a directory or a file, and prints them in a hierarchical way ?

• For any given filename list out all the stats related to the file such as size, creation time, path

#!/opt/python3

import os
import sys
import pwd    #Password db module

file = os.stat(sys.argv[1])

if file:
	print("File name is: %s" % sys.argv[1])
	print("The exact path: " + os.path.join(os.path.abspath(sys.argv[1])))
	print("File size: %d" % file.st_size + " bytes")
	print("File Owners UID is: %d" % file.st_uid)
	print("File Owners name: %s" % pwd.getpwuid(file.st_uid).pw_name)

os.stat( path ) - Get the status of a file or a file descriptor. Perform the equivalent of a stat() system call on the given path.

• st_size - Size of the file in bytes, if it is a regular file or a symbolic link

• st_uid - User identifier of the file owner

import pwd - This module provides access to the Unix user account and password database

• pwd.getpwuid(uid) - Return the password database entry for the given numeric user ID

• pw_name - Login name attribute in the pwd module

• pw_passwd - Displays the password in an encrypted format

os.path.join("path", "to", "folder") - It can handle join multiple paths, and take care of the right syntax for the current operating system

• os.path.abspath() - This function will convert the relative path to an absolute path by prefixing the current working directory to the path, Basically returns the absolute path of the sys.argv[1]

pwd — The password databasePython documentation

Have a read !

Another noob way to perform the above task would be directly calling the methods and attributes

#!/opt/python3

import os
import sys

statinfo = os.path.join(sys.argv[1])

ctime = os.path.getctime(statinfo)
path = os.path.abspath(statinfo)
size = os.path.getsize(statinfo) 
metadata = os.stat(statinfo)

print("The file creation time: " + str(ctime))
print("The exact path: " + path)
print("The size is: " + str(size) + " bytes")
print("Finally the metadata: " + str(metadata))

os — Miscellaneous operating system interfaces — Python 3.10.2 documentation

Have a read !