How to redirct stdout and stderr with command line

To redirect the standard output (stdout) and standard error (stderr) of a command from the command line, you can use the following techniques:

1. Redirect stdout to a file:

   command > output.txt
   

   This command will execute command and redirect its stdout to the output.txt file. If the file doesn’t exist, it will be created. If it already exists, the new output will overwrite the existing content.

2. Append stdout to a file:

   command >> output.txt
   

   This command will execute command and append its stdout to the output.txt file. If the file doesn’t exist, it will be created. If it already exists, the new output will be appended to the existing content.

3. Redirect stderr to a file:

   command 2> error.txt
   

   This command will execute command and redirect its stderr to the error.txt file. If the file doesn’t exist, it will be created. If it already exists, the new error output will overwrite the existing content.

4. Redirect both stdout and stderr to a file:

   command > output.txt 2> error.txt
   

   This command will execute command and redirect its stdout to the output.txt file, and its stderr to the error.txt file. Each output will be stored in a separate file.

5. Redirect stdout and stderr to the same file:

   command > output.txt 2>&1
   

   This command will execute command and redirect both its stdout and stderr to the output.txt file. The 2>&1 notation redirects stderr to the same location as stdout.

6. Discard stdout and stderr:

   command > /dev/null 2>&1
   

   This command will execute command and discard both its stdout and stderr. The > /dev/null redirects stdout to /dev/null, and 2>&1 redirects stderr to the same location, effectively discarding both outputs.

Remember to replace command with the actual command you want to execute, and output.txt and error.txt with the desired file names or paths.

By using these redirection techniques, you can control where the stdout and stderr of a command are directed, allowing you to capture, discard, or separate the outputs as needed.