How Shell Redirection and Pipes Work: >, >>, 2> and |

The article explains that every command has three text channels: stdin for input, stdout for normal results, and stderr for error messages. The > operator sends stdout to a file and overwrites it, while >> appends to the end of an existing file. Because stderr is stream 2, the 2> operator captures error messages separately, and 2>&1 merges errors into the same destination as normal output, with the order of redirections mattering. A pipe (|) passes one command's stdout directly into the next command's stdin, allowing small tools to be chained together. The piece notes that pipes carry only stdout, so errors from the left-hand command bypass the pipe.