Tee stdin to program
USAGE:
proctee [-o out] ... -- [prog ...]
Pipe stdin to stdout as-is, while teeing stdin to "prog ..." and piping
prog's stdout to one or more `out's.
-o Specifies the output file that the prog's stdout should be written to.
Multiple -o can be specified.
Visually:
STDIN --> STDOUT
|
v
prog
|
v
out1, out2, ...