How do I write standard error to a file while using "tee" with a pipe?

📝 Tech Blog: Writing Standard Error to a File with Tee and Pipe

Hey there tech enthusiasts! 👋 Are you struggling to write standard error to a file while using the "tee" command with a pipe? 🤔 Well, worry no more! In this guide, we'll address this common issue and provide you with easy solutions so you can conquer it like a boss! 💪

The Context

Let's start by understanding the context of the problem. You already know how to use tee to write the output (standard output) of a command like aaa.sh to a file named bbb.out, while still displaying it in the terminal. Here's the command you're already familiar with:

./aaa.sh | tee bbb.out

Now, the question arises: How can you write the standard error to a file named ccc.out while still having it displayed? 🤔

The Solution

Fortunately, the solution is not as complicated as it may seem. You can achieve this by redirecting the standard error to the same place as the standard output using the file descriptor for stderr (2) and then appending it to the file ccc.out. 📝

To accomplish this, you can use the following command:

./aaa.sh 2>&1 | tee -a bbb.out ccc.out

Let's break down this command:

1. ./aaa.sh: This is the command or script that generates both standard output and standard error.

2. 2>&1: This redirects the standard error (file descriptor 2) to the same location as the standard output (file descriptor 1).

3. |: This is the pipe operator, which connects the output of ./aaa.sh to the tee command.

4. tee -a bbb.out ccc.out: The -a flag ensures that the output is appended to the existing bbb.out file, and simultaneously, it writes the output to ccc.out.

By using this command, you can observe both the standard output and the standard error in your terminal, as well as have them written to their respective files. 🙌

Call to Action

Now that you know how to write standard error to a file using tee with a pipe, why not try it out yourself? 💡 Go ahead and experiment with redirecting different outputs to multiple files. Share your experiences, challenges, and cool tricks with us in the comments section below! Let's learn and grow together as a community of tech enthusiasts! 🚀

Remember, knowledge is power, but sharing knowledge is empowering! 🔥 So, don't keep this awesome trick to yourself – spread the word by sharing this blog post with your fellow techies! 👥

Keep coding, keep learning! 💻✨