Performance Boundaries

Loop Bound

Stop Work Early

Performance work starts by bounding how much work a loop can do. A clear limit keeps a script from processing more rows than the caller intended.

Program

Play the script to choose the loop limit and see how many items are processed.

loop_bound_plan.sh 
#!/usr/bin/env bash

limit=
count=0
for i in 1 2 3 4 5; do
    if [[ "$i" -gt "$limit" ]]; then
        break
    fi
    count=$((count + 1))
done
echo "processed=$count limit=$limit"

#!/usr/bin/env bash

limit=
count=0
for i in 1 2 3 4 5; do
    if [[ "$i" -gt "$limit" ]]; then
        break
    fi
    count=$((count + 1))
done
echo "processed=$count limit=$limit"
loop bound A loop bound limits how many iterations a script can perform.
early stop `break` exits the loop once the boundary is reached.
work count Counting processed items makes the boundary visible in output.