This article illustrates the regular expression search for go language files as an example. I will share it with you for your reference as follows:

package main
import (
    "fmt"
    "os"
    "path/filepath"
    "regexp"
)
func main() {
    //  Command line argument
    args := os.Args
    //  Check the parameters
    if len(args) == 1 {
        fmt.Println("ff is a file find tool. use like bottom")
        fmt.Println("ff [dir] [regexp]")
        return
    }
    if len(args) < 3 {
        fmt.Println("args < 3")
        return
    }
    fileName := args[1]
    pattern := args[2]
    file, err := os.Open(fileName)
    if err != nil {
        fmt.Println(err)
        return
    }
    fi, err := file.Stat()
    if err != nil {
        fmt.Println(err)
        return
    }
    if !fi.IsDir() {
        fmt.Println(fileName, " is not a dir")
    }
    reg, err := regexp.Compile(pattern)
    if err != nil {
        fmt.Println(err)
        return
    }
    //  Directory traversal
    filepath.Walk(fileName,
        func(path string, f os.FileInfo, err error) error {
            if err != nil {
                fmt.Println(err)
                return err
            }
            if f.IsDir() {
                return nil
            }
            //  Match the directory
            matched := reg.MatchString(f.Name())
            if matched {
                fmt.Println(path)
            }
            return nil
        })
}

PS: here are two more handy regular expression tools for you to use:

JavaScript regular expression online testing tool: http://tools.ofstack.com/regex/javascript

Online regular expression generation tool: http://tools.ofstack.com/regex/create\_reg

I hope this article has been helpful to you in the programming of Go language.