tail -f until another program exists?

[lawilog]

Hi,

from a bash script, i invoke a program ./foobar that creates a logfile.txt . Now I want to view the contents of logfile.txt while ./foobar is writing to it, but only until ./foobar finished.

So, e.g. I could use:

./foobar &
tail -f logfile.txt

...but then I get stuck in tail.

Is there an (elegant) way to do this?

Lars

[Kloschüssel]

./foobar | less

Surely not exactly what you're looking for, but this is the best thing I come up with.

[atreyu]

To slightly modify (i.e., complicate) K's suggestion:

#!/bin/sh
./foobar >logfile.txt 2>&1 &
while ps -p $! >/dev/null 2>&1; do
  clear
  cat logfile.txt
  sleep 1
done

[Rubberman]

Change foobar to write to stdout. Then you can do this:

./foobar | tail -f

If you still want the output to go to logfile.txt, then you can insert the tee command, as in:

./foobar | tee logfile.txt | tail -f

[lawilog]

thanks everybody.
today, i found another solution: tail has an --pid option!!

./foobar &
foobar_pid=$!
tail -f logile.txt --pid=$foobar_pid

[atreyu]

That is completely the best way, thanks for posting solution!