嵌套 for 循环 - 计数器变量为空

Question

我得到了以下脚本

#!/bin/bash
source ./settings.sh
for i in "${!PORTS[@]}"
do
  echo "INSTALLING DEPENDENCIES: $HOST:${PORTS[$i]}"
  ssh -p "${PORTS[$i]}" -i test-servers.pem ubuntu@$HOST /bin/bash << EOF 
    echo "username,password" > api-test/src/test/resources/users.csv
    for l in {1..5}
    do
        echo "${l}"
        echo "test${l}_${PORTS[$i]},1234" >> api-test/src/test/resources/users.csv
    done

    cat api-test/src/test/resources/users.csv
EOF
done

输出为：

INSTALLING DEPENDENCIES: 80.552.31.35:8000





username,password
test_8000,1234
test_8000,1234
test_8000,1234
test_8000,1234
test_8000,1234
INSTALLING DEPENDENCIES: 80.552.31.35:8001





username,password
test_8001,1234
test_8001,1234
test_8001,1234
test_8001,1234
test_8001,1234

为什么变量 l 是空的？如何获取计数器 (1,2,3,4,5) 并在 echo 中使用它？