I wanna insert new line with indent router.Use(apihandlers.AuthMiddleWare) after the specific word router := gin.Default().

func NewRouter() *gin.Engine {
    router := gin.Default()
    // I wanna insert line here.(with indent)
    //router.Use(apihandlers.AuthMiddleWare)
    for _, route := range RouteSettings {
        switch route.Method {
.
.
.
}

I try to implement it by sed command.
But It does not work now.
Maybe my Regular Expression is wrong.

sed -e '/^router := gin.Default()$/a router.Use(apihandlers.AuthMiddleWare)' {PATH_TO_THE_FILE}/routers.go

So please give me the correct Regular Expression.
Thanks in advance.

CodePudding user response：

I am not sure you can do it with a command if you want it to automatically use proper indent, but you can try with s. Here we capture both the indent and the rest of the line and replace it with:

• itself: \1\2
• new line: \n
• captured indent: \1
• new content: router...

sed -e 's/^\([[:space:]]*\)\(router := gin.Default()\)$/\1\2\n\1router.Use(apihandlers.AuthMiddleWare)/'

See https://ideone.com/kBzrni

CodePudding user response：

This might work for you (GNU sed):

sed '/router := gin\.Default()/{p;s/\S.*/line appended and indented/}' file

Match on the required line.

Print the required line.

Using the required line as a template, insert another line by overwriting the template line.