Question

I try to run a background job in a for loop in bash:

for i in $(seq 3); do echo $i ; sleep 2 & ; done

I get error:

bash: syntax error near unexpected token `;'

In zsh the command line works.

Answer 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