Figured another way to get an exit status of a job ran in background.
Obviously, these examples are simplified.
Each first of the two, is the 'one-liner' and the 2nd code box shows the structure with idention.
1) In this first one, we're sending the output of the background job into a variable, which we echo at the end.
This works, but doesnt really take advantage of a 'background' job.
ret=$(( sleep 2 ; [ -d not-existing ] ; echo $?) &)
echo $ret
ret=$(
(
sleep 2
[ -d not-existing ]
echo $?
)&
)
echo $ret
2) This one applies alot more to what one usualy expects as a background job. (AFAIU) mkfifo lets the read-command wait until something is written to its passed file.
tmp=~/.cache/$$~ ; mkfifo "$tmp"
( sleep 10 ; [ -d not-existing ] ; echo $? > "$tmp") &
read RET < "$tmp" ; [ "$RET" = "0" ] && echo "GOOD!" || echo "BAD"
rm -f "$tmp"
tmp=~/.cache/$$~
mkfifo "$tmp"
(
sleep 10
[ -d not-existing ]
echo $? > "$tmp"
) &
read RET < "$tmp"
[ "$RET" = "0" ] && echo "GOOD!" || echo "BAD"
rm -f "$tmp"
3) And to close the top 3, my most used code of these three.
This one loops while the background job is active and prints dots while its running. One could replace the printed string to update the text accordingly.
tmp="~/.cache/$~"
( sleep 5 ; [ -d not-existing ] ; echo $? > "$tmp") &
pid=$!
while ps $pid 1>/dev/zero;do sleep 0.5 ; printf ".";done
cat "$tmp"
tmp="~/.cache/$~"
(
sleep 5
[ -d not-existing ]
echo $? > "$tmp"
) &
pid=$!
while ps $pid 1>/dev/zero
do
sleep 0.5
printf "."
done
cat "$tmp"
Last but not least, i'll have a tool to help with such a task.
Its called: tui-psm, which names Text User Interface - Paralell Script Manager.
You can pass as many scripts as an array can hold, and limit the paralell executed scripts to any number you want (5 is default).
tui-psm script1.sh script2.bash script3.csh
But it can more, for example, if you need at least 3 scripts to be executed successfully before you attempt to run script 5, this could be your approach:
tui-psm -cq script1.sh script2.bash script3.csh ./script4.zsh
[ $? -ge 3 ] && ./script5.ash
Hope this helped.
Have fun scripting!
