Use tee to process a pipe with two or more processes

echo "tee can split a pipe in two"|tee >(rev) >(tr ' ' '_')
Tee can be used to split a pipe into multiple streams for one or more process to work it. You can add more " >()" for even more fun.
Sample Output
tee can split a pipe in two
tee_can_split_a_pipe_in_two
owt ni epip a tilps nac eet

33
By: axelabs
2010-08-14 20:38:59

1 Alternatives + Submit Alt

  • the tee command does fine with file names, but not so much with file descriptors, such as &2 (stderr). This uses process redirection to tee to the specified descriptor. In the sample output, it's being used to tee to stderr, which is connected with the terminal, and to wc -l, which is also outputting to the terminal. The result is the output of bash --version followed by the linecount Show Sample Output


    5
    tee >(cat - >&2)
    camocrazed · 2010-07-20 17:22:31 3

What Others Think

Cool trick! Unfortunately Cygwin has a bug in 1.7 that prevents this from working. AIX also has problems with it - it runs once but hangs after that. I thought it was leaving pipes around but it still hangs if I delete them from /tmp. Any help is much appreciated.
randy909 · 409 weeks and 4 days ago
My debian show this error: tee: /dev/fd/63: File or directory not found
n158 · 285 weeks ago
Here is the magic behind it: http://tldp.org/LDP/abs/html/process-sub.html
axelabs · 273 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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