Redirect Output and Error

Reference ▶️ ▶️ ▶️ How to Redirect Output and Error to /dev/null in Linux

Some thing about the output of linux

• In the linux machine, /dev/null that will location where you can return null for your shell like command 2>&1 /dev/null
• There will have 3 three type of output which linux has
  • Standard input (stdin) is designated with 0
  • Standard output (stdout) is designated with 1
  • Standard error (stderr) is designated with 2

What things we can play with this

1. Redirect output to /dev/null in Linux For example: You run apt install curl but you want your shell not return anything you can redirect output into /dev/null. It will be like

sudo apt install curl 1>/dev/null

Usage: Used it when you don’t want stdout go to your shell, just removing the odd things and keep the important output

2. Redirect error to /dev/null in Linux For example: You run find / but you run with non root, so somecase you will have some permission error output to your shell. You can use /dev/null for removing this messing stuff

find / 2> /dev/null

3. Awesome things, you can combine stdout and stderror into one with this character &

1. Long version
find / 2> /dev/null 1>/dev/null
 
2. Short version
find / 2>&1 /dev/null (Send error to output and send them to /dev/null)
 
3. Some other case
find / > /dev/null 2>&1

Troubleshoot

Sometime you can use version 2 of combining

The 2>&1 part means “redirect the error stream into the output stream”, so when you redirect the output stream, error stream gets redirected as well. Even if your program writes to stderr now, that output would be discarded as well. (Sergey Kalinichenko)

Find this problem ▶️ ▶️ What is /dev/null 2>&1?