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How are stdout and stderr used in Linux?
Linux has given us two file descriptors or channels to distinguish the Output and the Error so that we can redirect them to two different locations or files as per our requirement. Now having this basic understanding. let us go and see how to use this STDOUT and STDERR with Linux commands.
Can you write both stderr and stdout at the same time?
You can write both stderr and stdout to two separate files: To suppress the error messages from being displayed on the screen, redirect stderr to /dev/null: When saving the program’s output to a file, it is quite common to redirect stderr to stdout so that you can have everything in a single file.
How to redirect stderr to stdout in Bash?
The order of redirection is important. For example, the following example redirects only stdout to file. This happens because the stderr is redirected to stdout before the stdout was redirected to file. Another way to redirect stderr to stdout is to use the &> construct. In Bash &> has the same meaning as 2>&1:
Is there a way to save output to stdout?
When saving the program’s output to a file, it is quite common to redirect stderr to stdout so that you can have everything in a single file. To redirect stderr to stdout and have error messages sent to the same file as standard output, use the following:
How to echo something from stdout to stderr?
Consider the following script with two echo messages. The First echo command contains a string which supposed to go the STDERR but when you run this script you would get both these messages on the standard output or stdout So how to make echo command to echo something to the stderr instead of stdout.
How to suppress stderr messages in a bash script?
As UVV points out, the equivalent action from within the script is This redirects the stderr for the script to /dev/null from this statement until it is changed back. Clumsy ways of changing it back include which redirects stderr to the terminal. This is probably (but not necessarily) where it was originally.
Do you redirect error to stdout or stderr?
So we must redirect the error and output both into the same stream. Mostly we redirect the error (STDERR) into the output stream (STDOUT) and save both of them into a single file.