Paste the result of the tee command

Question

This is only hypothetical question - not solving any real problem - only learning bash.

With the tee command is possible split the output to more different streams, like:

command1 | tee >(commandA1 | commandA2 >file1) >(commandB1 | commandB2 >file2) >file0

so graphically is done the next

                  ---commandA1---commandA2--> file1
                 /
command1---tee-------> file0
                 \
                  ---commandB1---commandB2--> file2

Now, with the paste command can e.g.

paste file1 file2 | command3

but again i can redirect to the paste output from a different programs, like:

paste <(ls) <(ls) | command3

The question is: is possible somewhat join the two streams into one, something like

                  ---commandA1---commandA2---
                 /                           \
command1---tee-------> file0                  --- paste---command3
                 \                           /
                  ---commandB1---commandB2---

Ps: mean without intermediate files...

Answer 1

Here's how to do it with named pipes:

trap "rm -f /tmp/file1 /tmp/file2; exit 1" 0 1 2 3 13 15
mkfifo /tmp/file1
mkfifo /tmp/file2
command1 | tee >(commandA1 | commandA2 >/tmp/file1) >(commandB1 | commandB2 >/tmp/file2) >file0
paste /tmp/file1 /tmp/file2 | command3
rm -f /tmp/file1 /tmp/file2
trap 0

Working example:

$ cd -- "$(mktemp -d)" 
$ trap "rm -f pipe1 pipe2; exit 1" 0 1 2 3 13 15
$ mkfifo pipe1 pipe2
$ printf '%s\n' 'line 1' 'line 2' 'line 3' 'line 4' | tee \
>(sed 's/line /l/' | head -n 2 > pipe1) \
>(sed 's/line /Line #/' | tail -n 2 > pipe2) \
> original.txt
$ paste pipe1 pipe2 | sed 's/\t/ --- /'
l1 --- Line #3
l2 --- Line #4
$ rm pipe1 pipe2
$ trap 0