Redirecting shell command outputs to another konsole shell

First, look for the number that identifies the current tty session; lets consider the number as X:

| terminal 1               | terminal 2                |
 ------------------------------------------------------
| $ tty                    | $                         |
| /dev/pts/X               |                           |

Then, use the given number to write to the tty selected:

| terminal 1               | terminal 2                |
 ------------------------------------------------------
| $ tty                    | $ echo "foo" > /dev/pts/X |
| /dev/pts/X               |                           |

And it will produce:

| terminal 1               | terminal 2                |
 ------------------------------------------------------
| $ tty                    | $ echo "foo" > /dev/pts/X |
| /dev/pts/X               |                           |
| foo                      |                           |

You can pipe the output to a log file which is tailed by other sessions.

In any other terminal:

touch foo && tail -f foo

In the "main" terminal:

script.sh > foo