shell 逐行组合文本内容
#!/usr/bin/env bash
# ^^^^-- NOT /bin/sh
readarray -t a <n.txt # read each line of file1 into an element of the array "a"
readarray -t b <z.txt # read each line of file2 into an element of the array "b"
for itemA in "${a[@]}"; do
for itemB in "${b[@]}"; do
printf '%s%s\n' "$itemA" "$itemB"
done
done
