Why does os.symlink fail with directory paths and how can I mimic bash ln -sf in Python?

When you call os.symlink(source, link), you attempt to create a new symlink at the location given by link that points to source. If link already exists (or is a directory), the call fails.

Your bash command

BASHCopied
ln -sf $source/* $link

works differently—it iterates over all files/folders inside source and creates individual symlinks inside the link directory.

To replicate that behavior in Python, you need to:

1. Iterate over the contents of the source directory.
2. For each item found, create a symlink inside the destination directory.
3. Optionally, remove or overwrite an existing symlink or file in the destination before creating the new symlink.

Below is an example:

PYTHONCopied
import os
import glob

source = '/var/source/things'
link = '/var/link'

# Ensure the destination directory exists.
if not os.path.exists(link):
    os.makedirs(link)

# Iterate over each item in the source directory.
for item in glob.glob(os.path.join(source, '*')):
    # Determine the basename of the item.
    item_name = os.path.basename(item)
    # Construct the destination path inside the link directory.
    dest = os.path.join(link, item_name)

    # If the destination already exists (symlink, file, or directory), remove it.
    if os.path.lexists(dest):
        os.remove(dest)
        
    # Create a symbolic link at dest that points to the item.
    os.symlink(item, dest)

Key Points

• os.symlink(source, link_name):
  Creates a symlink at the location link_name that points to source.
• Checking for Existing Destination:
  Use os.path.lexists(dest) to check if the link (or file/directory) exists regardless of its validity, then remove it.
• Iteration Over Contents:
  Using glob to iterate over each file/folder inside the source directory ensures that you mimic the bash command behavior of linking each item individually.

This approach achieves a similar end result to your bash script by creating individual symlinks for every entry within the source directory into the destination directory.