tpipe is similar to tee(1) except that tpipe writes the duplicate copy of its standard input to a command or pipeline instead of a file. This can help you avoid re-executing earlier commands in the pipeline, writing temporary files, or resorting to the use of named pipes.
The specified pipeline is always executed in a subshell by sh(1), regardless of your current shell. If a non-empty string is supplied as the argument, it must be a valid pipeline or command for sh(1). Normally, you will want to enclose the pipeline argument in quotes ('' or ""). The type of quotes you choose will affect variable substitution by your shell (see the man page for your shell, such as csh(1), for details).
If the subshell pipeline writes to its standard output, this output will go to the standard output of tpipe, where it will be interspersed in an unpredictable way with the other copy of standard input. Normally, this is not what you want. Instead, you would typically specify a subshell pipeline whose output is redirected to a file (as in the example below) or has some other effect.
which has the effect of running the output of command cmd1 simultaneously through two pipelines, "cmd2 | cmd3 >outfile" and cmd4. Diagramatically, in this example (this will look wrong with a variable-spaced font):
--> cmd2 --> cmd3 --> outfile
/
infile --> cmd1 -<
\
--> cmd4 --> (standard output)
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