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bash shell脚本for循环中的两个变量

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bash shell脚本for循环中的两个变量 
for SLAVE_CLUSTER,MASTER_CLUSTER in $MASTER_CLUSTERS $SLAVE_CLUSTERS
do
      echo "Master cluster boxes are ${!MASTER_CLUSTER}"
      echo "Slave cluster boxes are ${!SLAVE_CLUSTER}"
done

我试图在一个 for 循环中获取SLAVE_CLUSTER,的值，MASTER_CLUSTER但出现错误。我们怎样才能在一个for循环中同时获取这两个变量呢？

这是我的主从集群变量

export MASTER_CLUSTER_1="MASTER1 MASTER2"
echo "MASTER_CLUSTER_1 = $MASTER_CLUSTER_1"
export MASTER_CLUSTER_2="MASTER1 MASTER2"
echo "MASTER_CLUSTER_2 = $MASTER_CLUSTER_2"
export SLAVE_CLUSTER_1="SLAVE1 SLAVE2 SLAVE3 SLAVE4"
echo "SLAVE_CLUSTER_1 = $SLAVE_CLUSTER_1"
export SLAVE_CLUSTER_2="SLAVE1 SLAVE2 SLAVE3 SLAVE4"
echo "SLAVE_CLUSTER_2 = $SLAVE_CLUSTER_2"

答案1

我不确定我是否理解您对单个循环的需求。您可以使用这样的两个连续循环获得相同的输出

for MASTER_CLUSTER in $MASTER_CLUSTERS

    do
          echo "Master cluster boxes are ${!MASTER_CLUSTER}"
    done

for SLAVE_CLUSTER in $SLAVE_CLUSTERS
    do
          echo "Slave cluster boxes are ${!SLAVE_CLUSTER}"
    done

或者如果这些值必须交替，那么

for MASTER_CLUSTER in $MASTER_CLUSTERS
    do 
    echo "Master cluster boxes are ${!MASTER_CLUSTER}"
    for SLAVE_CLUSTER in $SLAVE_CLUSTERS
       do
          echo "Slave cluster boxes are ${!SLAVE_CLUSTER}"
       done
    done

答案2

根据OP的澄清扩展我的答案。同样，您可以使用数组：

$ cat /tmp/foo.sh
#/bin/bash

# Sample values from OP
export MASTER_CLUSTER_1="MASTER1 MASTER2"
export MASTER_CLUSTER_2="MASTER3 MASTER4" # (edited to be unique)
export SLAVE_CLUSTER_1="SLAVE1 SLAVE2 SLAVE3 SLAVE4"
export SLAVE_CLUSTER_2="SLAVE5 SLAVE6 SLAVE7 SLAVE8" # (edited to be unique)

# Create two arrays, one for masters and one for slaves.  Each array has
# two elements -- strings containing space delimited hosts
declare -a master_array=( "${MASTER_CLUSTER_1}" "${MASTER_CLUSTER_2}" )
declare -a slave_array=( "${SLAVE_CLUSTER_1}" "${SLAVE_CLUSTER_2}" )

# For this to work, both arrays need to have the same number of elements
if [[ "${#master_array[@]}" == ${#slave_array[@]} ]]; then
    for ((i = 0; i < ${#master_array[@]}; ++i)); do
        echo "master: ${master_array[$i]}, slave: ${slave_array[$i]}"
    done
fi

示例输出：

$ bash /tmp/foo.sh
master: MASTER1 MASTER2, slave: SLAVE1 SLAVE2 SLAVE3 SLAVE4
master: MASTER3 MASTER4, slave: SLAVE5 SLAVE6 SLAVE7 SLAVE8

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