How to save cURL output to file

cURL is a command-line utility for performing web requests that output the response to the terminal. cURL is used for various tasks, including retrieving a webpage's HTML, downloading files, or interacting with API endpoints.

Saving the cURL response to a file allows for later review, processing, or sharing, circumventing the constraints of terminal-based viewing. This approach is particularly beneficial for handling large or binary files or when the output needs to be shared.

There are multiple methods for saving a cURL command's output to a file based on the data type and required result. These methods include redirecting the terminal output to a file, appending the output to an existing file, or saving the output to a file directly.

1. Open the terminal or command prompt.
2. Execute your cURL command followed by the > symbol and the desired output filename.

   $ curl https://www.example.com/ > output.txt

3. To append data to an existing file rather than overwriting it, use ».

   $ curl https://www.example.com/moredata > output.txt

   Using » ensures that the previous data in the file remains intact and new data gets appended to it.

4. For capturing both the response and error messages, use 2>.

   $ curl https://invalid.url 2> errorlog.txt

   2> directs standard error (often used for error messages) to the designated file.

5. If you wish to save both the output and error messages to the same file, combine the commands.

   $ curl https://invalid.url > output.txt 2>&1

   Here, 2>&1 tells the shell to redirect the standard error (2) to the same location as the standard output (1).

6. Review the content of the saved file.

   $ cat output.txt

7. In case you're working with binary files like images, use the -o option.

   $ curl -O https://www.example.com/image.jpg

   The -O flag tells cURL to save the output in a file with the same name as the remote file. Use -o with a filename to specify a different name.

8. Secure your output file if it contains sensitive data.

   $ chmod 600 output.txt

   It's a best practice to set appropriate permissions on files that hold confidential or sensitive information.