redirecting stdout and stderr to file using bash

Question

In order to redirect stdout to a file in bash I use:

cmd > file.txt

To redirect stdout using Bash while appending I use:

cmd >> file.txt

and for both stdout and stderr to a truncated file I use:

cmd &> file.txt

How do I redirect both stdout and stderr appending to a file? cmd &>> file.txt did not work for me

But I want to redirect both stdout and stderr appending to a file. How do I do that?

Answer 1

cmd >>file.txt 2>&1

Bash always executes and redirects from left to right:

1. >>file.txt: simply opens the text file in append mode and puts the stdout there
2. 2>&1: this redirects stderr to the same place where stdout is ging. which in this case is the file opened in append mode. The &1 is using the descriptor which was being used by stdout