With an interval
for i in {1..10};
do
echo "line $i"
done
Loop through filenames:
for file in *.json; do
ls -l $file
done
Loop using the output of a subcommand:
for file in $(find . -name '*.json'); do
ls -l $file
done
Single liner:
for i in {1..5}; do echo $i; done