Nested loops means loops inside loops. Check out the following example:
#!/bin/bash for (( v1 = 1; v1 <= 3; v1++ )) do echo "First loop $v1:" for (( v2 = 1; v2 <= 3; v2++ )) do echo " Second loop: $v2" done done
The first loop hits first, then the second loop, and this happens three times.