tee can be used to duplicate stdout to stderr

[frederic-mahe]

It took me a while to figure it out. As it might be useful for someone else, I propose to add it here.

[pkrumins]

Can you show an example here?

[frederic-mahe]

Sure:

echo "Foo" | tee /dev/stderr

will print "Foo" twice (on stdout and stderr). I reviewed a script in which the same message was echoed twice: once to the stdout, and a second time to the stderr. To remove that code duplication, I proposed to use the tee command. In my opinion, the interesting reminder here is that you can tee to a file, but also to any other device.

[pkrumins]

Cool example! I need to see how it looks in the final cheat sheet. It's tight on space for more examples.