How do I redirect stderr and stdout?

October 14, 2019 Off By idswater

How do I redirect stderr and stdout?

To redirect stderr as well, you have a few choices:

  1. Redirect stdout to one file and stderr to another file: command > out 2>error.
  2. Redirect stdout to a file ( >out ), and then redirect stderr to stdout ( 2>&1 ): command >out 2>&1.

How do you write to Dev Null?

You write to /dev/null every time you use it in a command such as touch file 2> /dev/null. You read from /dev/null every time you empty an existing file using a command such as cat /dev/null > bigfile or just > bigfile. Because of the file’s nature, you can’t change it in any way; you can only use it.

Is writing to Dev Null faster?

Yes, /dev/null is as fast as an output file descriptor can possibly be without kernel hacking, and even then it’d be hard to beat. I picked this answer for the additions in comment.

How do I send an error to Dev Null?

In Unix, how do I redirect error messages to /dev/null? You can send output to /dev/null, by using command >/dev/null syntax. However, this will not work when command will use the standard error (FD # 2). So you need to modify >/dev/null as follows to redirect both output and errors to /dev/null.

How to redirect stderr to / dev / null?

I want to get rid of this message, so I tried to redirect stderr to /dev/null, but somehow this is not working. I want to preserve stdout (i.e. write the results to the console), and only hide these grep error messages. Instead of 2>, I also tried &>, but this also did not work. How can I fix this? You don’t need xargs here.

How to send output to / dev / null?

You can send output to /dev/null, by using command >/dev/null syntax. However, this will not work when command will use the standard error (FD # 2). So you need to modify >/dev/null as follows to redirect both output and errors to /dev/null. Syntax to redirect error and output messages to /dev/null

How to set stdout to / dev / null?

Well, that’s because you can’t. STDOUT and STDERR are just two files, represented by file descriptors, which are just integers, specifically 1 and 2. What you’re asking is to set descriptor 2 to /dev/null, then set descriptor 3 to the same file descriptor 2 and have that output go somewhere else.

How to redirect stdin and stderr to output file?

You can always redirect both standard error (stdin) and standard out (stdout) text to an output file or a log file by typing the following command: command > file 2>&1 / path / to / my / cool / appname > myapp.log 2>&1 Want to close stdout and stderr for the command being executed on a Linux/Unix/BSD/OSX bash shell? Try the following syntax: