pipetee

A simple, fast, no-dependencies UNIX utility to print the contents of stdin to the terminal and forward them to stdout at the same time.

Example usage:

# output from pt will interleave with output from
# sed at the granularity of the buffer

$ yes 'yes' | pt | sed 's/yes/no/g'
no
no
no
no
no
..
no
yes
yes
yes
yes
yes
..
yes
no
no
no
no
no
..
no
^C

$ yes 'yes' | ./target/release/pt -b 3 | sed 's/yes/no/g'
yeno
s
yno
es
no
no
yesno
no
no

yes
yno
es
no
no
yesno
no
^C

# look at intermediate results if the final output takes a long time.
$ cat numbers.txt | ./computation-with-incremental-results.py | pt | sort -n | tee output.txt
# unsorted
0.0030632556724745847
0.0018044960059851569
0.001587923806107082
0.0029520906739906577
0.006344797296449427
0.1628663298523446
0.10106032701405257
0.028920997961789503
0.027188567279582024
0.02568497042514556
# sorted
0.001587923806107082
0.0018044960059851569
0.0029520906739906577
0.0030632556724745847
0.006344797296449427
0.02568497042514556
0.027188567279582024
0.028920997961789503
0.10106032701405257
0.1628663298523446

How does it work?

It reads from stdin and writes to both stdout and /dev/tty. Your shell will redirect stdout to whatever the next pipe is, but /dev/tty (what stdout defaults to on most shells) will remain untouched.