在 shell 脚本的 for 循环中逐行迭代文本文件

Question

我有一个看起来像这样的 txt 文件，名为 locations.txt：

location-1a
location-2c
location-3d
location-4
location-5a
...

我希望在我的 for 循环中遍历 locations.txt 文件，每个位置应该用于 5 个节点，然后应该使用下一个位置。例如，我希望运行以下命令，

server create --location location-1a node-1
server create --location location-1a node-2
server create --location location-1a node-3
server create --location location-1a node-4
server create --location location-1a node-5
server create --location location-2c node-6

.....

到目前为止，我只有以下名为 script.sh 的脚本，它从 cli 中获取参数。我无法随意更改位置。

mapfile -t locationArr < ~/Documents/files/locations.txt
serverCounter=1
locationCounter=1
counter=1

counter=1
for (( i = 1; i <= $1; i++ ))
do
 server create --location $locationArr[$locationCounter] node-$i
 counter=$((counter+1))
 if [ $counter == 5 ]
 then
  counter=1
  locationCounter=$((locationCounter+1))
done

我想要类似的东西

if counter == 5:
 counter=0
 nextline 

例如，如果我运行script.sh 11，我想要以下结果，

server create --location location-1a node-1
server create --location location-1a node-2
server create --location location-1a node-3
server create --location location-1a node-4
server create --location location-1a node-5
server create --location location-2c node-6
server create --location location-2c node-7
server create --location location-2c node-8
server create --location location-2c node-9
server create --location location-2c node-10
server create --location location-3d node-11

如何在我的 for 循环中遍历 location.txt 文件？我应该将文本文件转换为某种列表变量吗？

Answer 1

这是我的尝试：

counter=1
while IFS= read -r line
do
    for (( i=1; i <= 5 && $counter <= $1; i++ ))
    do
     server create --location $line node-$counter
     counter=$((counter+1))
    done 
done < ~/Documents/files/locations.txt

11 的输出：

server create --location location-1a node-1
server create --location location-1a node-2
server create --location location-1a node-3
server create --location location-1a node-4
server create --location location-1a node-5
server create --location location-2c node-6
server create --location location-2c node-7
server create --location location-2c node-8
server create --location location-2c node-9
server create --location location-2c node-10
server create --location location-3d node-11

Answer 2

总纲：

• 从locations.txt读取位置的外循环
• 用于为给定位置生成最多 5 个节点的内部循环
• 每次生成一个节点时都会增加一个计数
• 如果计数器 > 输入 'max' 然后跳出循环

上述的一种实现：

max=${1}
curr=1

while read -r location
do
    for i in {1..5}
    do
        echo "server create --location ${location} node-${curr}"
        curr=$((curr+1))
        [ ${curr} -gt ${max} ] && break 2
    done
done < locations.txt

使用max=${1}=11 测试运行：

server create --location location-1a node-1
server create --location location-1a node-2
server create --location location-1a node-3
server create --location location-1a node-4
server create --location location-1a node-5
server create --location location-2c node-6
server create --location location-2c node-7
server create --location location-2c node-8
server create --location location-2c node-9
server create --location location-2c node-10
server create --location location-3d node-11

OP 可以添加额外检查 max 是否为大于 0 的整数。

Answer 3

用单循环完成，没有 Bashism POSIX 语法：

#!/usr/bin/env sh

i=0
while [ $i -lt "$1" ] && {
  [ $((i % 5)) -ne 0 ] || IFS= read -r line || [ "$line" ]
}; do
  server create --location "$line" "node-$((i = i + 1))"
done <locations.txt