Loop background job
Solution 1:
Remove the ; after sleep
for i in $(seq 3); do echo $i ; sleep 2 & done
BTW, such loops are better written on separate lines with proper indentation (if you are writing this in a shell script file).
for i in $(seq 3)
do
echo $i
sleep 2 &
done
Solution 2:
You can put the background command in ( )
for i in $(seq 3); do echo $i ; (sleep 2 &) ; done