linux - Shell 脚本未运行

Question

当我执行下面的脚本时，它只是坐在那里没有输出。有什么想法吗？

#!/bin/bash
for k in `seq 0 4`
do
for c1 in `seq 1 30`
do
for c2 in `seq $c1 30`
do
for b1 in `seq 1 $c1`
do
for b2 in `seq $b1 $c2`
do
for s1 in `seq 0 (($c1 - $b1))`
do
for s2 in `seq 0 (($c2 - $b2))`
do
    echo "k: $k - c1: $c1 - c2: $c2 - b1: $b1 - b2: $b2 - s1: $s1 - s2: $s2"
done
done
done
done
done    
done
done

Answer 1

seq 语句之一无限期地运行。您缺少一些美元符号:

for s1 in `seq 0 $(($c1 - $b1))`

for s2 in `seq 0 $(($c2 - $b2))`