Copy input sent to a command to stderr

rev <<< 'lorem ipsum' | tee /dev/stderr | rev
In the above example 'muspi merol' (the output of the first rev command) is sent to stderr and 'lorem ipsum' (the output of the second rev command) is sent to stdout. rev reverse lines of a file or files. This use of tee allows testing if a program correctly handles its input without using files that hold the data.
Sample Output
muspi merol
lorem ipsum

2
By: penpen
2009-03-31 13:12:09

What Others Think

'echo 'lorem ipsum'| rev | tee /dev/stderr | rev' reads cleaner.
ozymandias · 554 weeks ago
@ozymandias: Hint: "To include further commands, include them on a new line that starts with a $." also applies to comments, next time try using it because echo 'lorem ipsum' | rev | tee /dev/stderr | rev immediately sticks out as code.
penpen · 554 weeks ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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