Some nice tee

I wanted to log something in bash to the console and to a log file.
Turns out there’s a command for that

tee

more information here

So a very simple example would be

ls | tee test.txt  

which will display the output of ls to the screen and store the result in the file test.txt.

By default it overwrites the file, if you want an ongoing log use the -a option

ls | tee -a test.txt  

If you want errors as well, also useful for a log file, redirect stderr to stdout

ls -e 2>&1 | tee -a text.txt  

The test.txt file will contain the error about -e being an invalid option