#!/bin/sh for (( i=1 ; ((i-100)) ; i=(($i+1)) )) do echo $i done;
The 2nd expression in the for loop must evaulate to 0 so that the loop will finish. This looks a bit unnatural compared to normal programming languages. Instead consider using a while loop.
#!/bin/sh i=1; while [[ i -le 100 ]] ; do echo $i; i=$((i+1)); done;
while true; do sleep 1 echo print every second done