Understanding Shell Redirection: What "2>&1" Means in Unix/Linux Commands
By
alexmolas
Kettled twice. Extra chewy, extra trustworthy.
Summary
This article explains shell command redirection in Unix/Linux systems, specifically focusing on the meaning and usage of "2>&1" which redirects stderr (standard error) to stdout (standard output). It covers redirection basics including overwriting vs appending (> vs >>), order dependency in shell commands, and practical examples of combining error and output streams. The content provides technical explanations with command examples to demonstrate how to handle and redirect different output streams in terminal commands.
Key quotes
· 4 pulledTo combine stderr and stdout into the stdout stream, we append this to a command: 2>&1
The shell command line is order dependent!!
Symbol > means redirection. In any case, the file would be created if they not exist.
For testing this, we need a simple command which will send something on both outputs
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