Stderr and stdout to file bash

If you look at the preceding command you can see that we are trying to list two files at the same time. Amongst them, one is not present. As said earlier, By Default both stdout and stderr would be displayed in the stdout channel only. In the previous command, we just redirected the stderr into the file and displayed the standard output on the terminal. But If we want to redirect the stdout and stderr to two different files at the same time.

In the preceding command, you can notice we are using the same strategy of prefixing the file descriptor numeric value of stdout and stderr with the redirection symbols followed by the appropriate file names. Hope it helped you to understand the stdout and stderr and how to use them.

We all know that the bash echo command prints everything that you give after that. In fact, echo command does not even return any error or nonzero return code. Consider the following script with two echo messages. We are going to apply the same trick of file descriptors and redirection symbol.

In most cases, we would be redirecting the error stream to output stream so that we do not miss anything or to stop it from being printed on the terminal. In other words,. The best example is while scheduling a cron job. However, your command doesn't work either. I'm editing my answer to remove the first example. As UNIX allows deleting open files, the stdout is now logged to file that used to be called my.

Once the last filehandle to that file is closed, the file contents will be also deleted. And according to POSIX rules, file handle 1 is always stdout and 2 is always stderr so stderr then points to already opened file my. Pradeep Goswami Pradeep Goswami 1, 1 1 gold badge 14 14 silver badges 22 22 bronze badges.

This is the correct answer if you want to see the output in the terminal, too. However, this was not the question originally asked.

A B A B 1, 2 2 gold badges 20 20 silver badges 22 22 bronze badges. Why does this answer even exist when it's included in TheBonsai's answer? Please consider deleting it. You'll get a disciplined badge. Sorry for that: Here comes some additional tips. Zhou Quintus. Zhou 9 9 silver badges 13 13 bronze badges. Additionally it will not append to the file but it will overwrite it.

Correct: File descriptor could be any values which is more than 3 for all other files. Order of the redirections matters. Zhou Yup. Your version redirects err to out, and at the same time out to file. Show 1 more comment. Redirect the new standard output by appending to a file. If stderr is redirected to stdout first, use the below-given command to redirect the stdout to a file. All of the shells do not support this form redirection, but bash and Zsh support it.

Stdout and stderr can be redirected by utilizing the following syntax. In the upcoming section of the article, we will check out the separate example for stdout and stderr redirection. The syntax for redirecting the stdout to a file is given as follow:. Next, you have seen the practical example for various forms of stdout and stderr redirection.

Talha is a contributor at Linux Hint with a vision to bring value and do useful things for the world. Why do you need an ampersand here? How would write to a file named 1 otherwise? The Overflow Blog. Podcast Making Agile work for data science. Stack Gives Back Featured on Meta. New post summary designs on greatest hits now, everywhere else eventually. Linked See more linked questions.