Streams & Piping
Every command in Windows has three standard "streams":
- STDIN (0): Standard Input (Keyboard)
- STDOUT (1): Standard Output (Screen)
- STDERR (2): Standard Error (Screen)
By manipulating these streams, you can save potential errors to a log file, chain commands together, or automate input.
Common Scenarios
1. The Pipe (|)
Passes the output of one command as input to the next.
Example: List files and find specific ones.
dir | find "txt"
2. Output Redirection (>) and (>>)
Save results to a file.
Example: Save ipconfig details.
ipconfig > network_info.txt
3. Error Redirection (2>)
Separate clean output from error messages.
Example: Hiding errors when deleting non-existent files.
del non_existent_file.txt 2> nul
(Sending to nul effectively discards the output)
Real-World Examples
1. Sorting Output
List text files and sort them by name.
2. Logging Errors Separately
Try to list a folder that doesn't exist, and save the error.
Knowledge Check
1 / 3Which number represents Standard Error (STDERR)?
References
These Microsoft Learn and Windows documentation links provide authoritative details for the commands used in this article.