5 Levels of Handling I/O Redirection in Linux

Redirecting the stdout, stderr and stdin like a guru

Image from Wallhaven

Yesterday, my colleague asked me a very interesting question about a Linux script she found on our server:

What does the following line of command mean?

date >> daily_log.txt 2>&1

I smiled and kindly told her the details as always. 🙂

This is about the redirection of standard output and standard error in Linux.

Basically, there are 3 types of standard I/O in Linux:

• Standard output (stdout)
• Standard error (stderr)
• Standard input (stdin)

This article will reveal the secrets of the above command and give you a comprehensive guide about the tips and tricks of the I/O redirection on Linux.

1. Redirecting Standard Output to a File

In some cases, it’s necessary to save the results of a command into a file for future usage instead of printing them on the standard output. To implement it, all we need is just the > operator:

date > log.txt

The above command saves the result of the date command into a file named log.txt through the >…