linux - 如何通过字符串组装变量

Question

我有以下 shell 脚本，假设它的名称为 test.sh

#!/bin/bash
b_x='it is the value of bx'
c_x='it is the value of cx'

case "$1" in
    "b")
       echo $1_x    # it's doesn't work; I want to echo $b_x
       ;;
     "c")
       echo $1_x   # it's doesn't work; I want to echo $c_x
       ;;
esac

然后我想调用脚本；

./test.sh  b    # I want the output is "it is the value of bx"
./test.sh  c    # I want the output is "it is the value of cx"

Answer 1

你不需要case。只需使用间接变量名扩展:

b_x='it is the value of bx'
c_x='it is the value of cx'

var="${1}_x"
echo "${!var}"

然后运行它:

$> bash test.sh b
it is the value of bx

$> bash test.sh c
it is the value of cx