How to log output and see it at the same time?

How to log output and see it at the same time?

How to log output in bash and see it in the terminal at the same time? I have some scripts where I need to see the output and log the result to a file, with the simplest example being: I want to be able to see the output of the command while it’s running, but also have it logged to the file.

How to see output in terminal at the same time?

I have a script that outputs text to stdout. I want to see all this output in my terminal, and at the same time I want to filter some lines and save them in a file. Example: I want to see output of first command in terminal, and save the output of the second command in a file. At the same time.

How to log output in Bash and see it in the terminal?

If you want to log errors (from stderr), use: This means: run command and redirect the stderr stream (2) to stdout (1). That will be passed to the pipe with the tee application. Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question.

Can You redirect LS output to a file?

I am doing following and it appending to file but not printing ls output on terminal. Yes, if you redirect the output, it won’t appear on the console. Use tee. It is worth mentioning that 2>&1 means that standard error will be redirected too, together with standard output.

Is the output stream visible in the terminal?

The standard output stream will be redirected to the file only, it will not be visible in the terminal. If the file already exists, the new data will get appended to the end of the file.

How to get the output of a command?

If you use a sequence of commands, you may want to get output&error of all of them, one after another. In this case you can use -a flag to “tee” command: In case somebody needs to append the output and not overriding, it is possible to use “-a” or “–append” option of “tee” command :

How to write output to stdout and log file?

The /tmp/both.log is appended unless you remove the -a from tee. Hint: > (…) is a process substitution. It lets the exec to the tee command as if it were a file. I wanted to display logs on stdout and log file along with the timestamp. None of the above answers worked for me.

How to write a message to both the console and the log file?

to write a message to both the console and the log file – tee sends its output to both its own fd 1 (which here is the LOG_FILE) and the file you told it to write to (which here is fd 3, i.e. the console). Example: into the log file. It worked just as you suggested.

How to log errors from stderr to stdout?

Please note that the pipe will catch stdout only, errors to stderr are not processed by the pipe with tee. If you want to log errors (from stderr), use: This means: run command and redirect the stderr stream (2) to stdout (1). That will be passed to the pipe with the tee application.

How to output both stderr and stdout at the same time?

Here, stdout remains the screen, since it wasn’t redirected. myfile.txt will contain ERR. Then, if you want to output both, and still catch stderr into a file, you’ll probably have to go in two steps with a little command substitution…