Golang : Pad file extension automagically

Problem:

You want to pad file type extension to a given filename string without prompting your program users to do so. Your program accepts extension of certain type only. How to pad the missing file type extension automatically?

Solution:

Use strings.HasSuffix() function to detect if the filename string has the file type extension. If not, pad the filename string with the file extension type.

Here you go!

---

 package main

 import (
 "strings"
 "os"
 "fmt"
 )

 func main() {

 if len(os.Args) != 2 {
 fmt.Printf("Usage : %s <filename.ext>\n", os.Args[0])
 os.Exit(0)
 }

 inputFileName := os.Args[1]

 fmt.Println("Input file name is : ", inputFileName)

 if !strings.HasSuffix(inputFileName, ".ext") { // check if the .ext is in the string 
 fmt.Println("Input file name does not have extension. Padding now")
 inputFileName += ".ext"
 fmt.Println("Input file name with extension padded : ", inputFileName)
 } else {
 fmt.Println("Input file name already has extension : ", inputFileName)
 }
 }

---

Sample outputs:

./padfileextent testfilenamewithoutextension.bmp

Input file name is : testfilenamewithoutextension.bmp

Input file name does not have extension. Padding now

Input file name with extension padded : testfilenamewithoutextension.bmp.ext

NOTE : Still pad with .ext because the filename does not have the required extension

---

./padfileextent testfilenamewithoutextension

Input file name is : testfilenamewithoutextension

Input file name does not have extension. Padding now

Input file name with extension padded : testfilenamewithoutextension.ext

---

./padfileextent testfilenamewithoutextension.ext

Input file name is : testfilenamewithoutextension.ext

Input file name already has extension : testfilenamewithoutextension.ext

---

References:

https://www.socketloop.com/tutorials/golang-get-command-line-arguments