很多时候,需要将一行字符分割成多个变量,例如处理文本
这里需要注意,默认分割符是空格,如果是不同分割符,则需要设置 IFS
IFS="," read -r v_space v_email v_name v_sn <<< ",myname@example.com,不一样的烟火,123456"
然后我们就可以随便使用变量了
显示输出
json和多变量案例
我在结合上述方法,采用循环方式根据 app
名字访问API来获得应用的配置(json)。
例如,单条命令
app=ABC
AK=XXXXXXXX
curl -s --location --request GET "http://api.example.com/getAppInfo.json?appName=$app" --header "apiauth-token: $AK" | jq
可以获得某个应用的信息如下
{
"app": {
...
"owner": {
...
"email": "xyz@example.com",
"nickName": "dogfood",
"staffNo": "123",
...
},
...
则我通过jq多变量读取:
curl -s --location --request GET "http://api.example.com/getAppInfo.json?appName=$app" --header "apiauth-token: $AK" | jq -r '.app.owner | .email + "," + .nickName + "," + .staffNo'
可以输出
xyz@example.com,dogfood,123
然后我们可以通过多变量赋值直接读取到3个变量,方便后续shell处理
IFS="," read -r owner_email owner_nickName onwer_staffNo <<< $(curl -s --location --request GET "http://api.example.com/getAppInfo.json?appName=$app" --header "apiauth-token: $AK" | jq -r '.app.owner | .email + "," + .nickName + "," + .staffNo')
不过,上述采用 $()
来把执行结果转换为字符串变量然后通过 <<<
输入给左边3个变量的方法,如果使用了循环,则只能在高版本bash上正常工作(例如bash 4.4.19):
for app in `cat $APP_LIST`; do
IFS="," read -r owner_email owner_nickName onwer_staffNo <<< $(curl -s --location --request GET "http://api.example.com/getAppInfo.json?appName=$app" --header "apiauth-token: $AK" | jq -r '.app.owner | .email + "," + .nickName + "," + .staffNo')
echo "owner_nickName: $owner_email"
echo "owner_email: $owner_nickName"
echo "onwer_staffNo: $onwer_staffNo"
done
则在 macOS的bash 3.2.57上执行结果是错误的
owner_email: xyz@example.com dogfood 123
owner_nickName:
onwer_staffNo:
...
但是,如果运行环境是高版本 bash 4.4.19 (linux),则完全正常
owner_email: xyz@example.com
owner_nickName: dogfood
onwer_staffNo: 123
...
为了兼容低版本bash,脚本需要修订成 <<<
右边直接使用字符串变量 "$string"
:
for app in `cat $APP_LIST`; do
AppInfo=`curl -s --location --request GET "http://api.example.com/getAppInfo.json?appName=$app" --header "apiauth-token: $AK" | jq -r '.app.owner | .email + "," + .nickName + "," + .staffNo'`
IFS="," read -r owner_email owner_nickName onwer_staffNo <<< "$AppInfo"
done
则通用能够正常工作输出正确结果
参考