====== dos2unix: Handling Permission Errors ======

===== Overview =====

When converting a file from Windows (DOS) line endings to Unix line endings, the usual `dos2unix` syntax may sometimes result in a **permission error**.

For example:

<code bash>
dos2unix filename
</code>

may produce an error similar to:

<code>
dos2unix: Failed to change the permissions of temporary output file: Operation not permitted
</code>

> This can happen when `dos2unix` does not have the necessary permissions to modify or replace the original file.

===== Solution =====

Instead of converting the file in-place using the standard syntax, use the `-n` option to explicitly specify an input (source) file and an output (target) file:

<code bash>
dos2unix -n <source_file> <target_file>
</code>

For example:

<code bash>
dos2unix -n input.txt output.txt
</code>

This converts `input.txt` to Unix line endings and saves the result as `output.txt`, leaving the original file unchanged.

===== Overwriting the Original File =====

If you want to convert the file while keeping the same filename, you can specify the same path as both the source and target:

<code bash>
dos2unix -n /path/to/file.txt /path/to/file.txt
</code>

This rewrites the file in Unix format without relying on `dos2unix` to replace the original file in the usual way.

===== Summary =====

| Command                             | Purpose                                 |
| ----------------------------------- | --------------------------------------- |
| `dos2unix file.txt`                 | Convert a file in-place (may throw an error |
| `dos2unix -n source.txt target.txt` | Convert to a separate new file          |
| `dos2unix -n file.txt file.txt`     | Convert while keeping the same filename |