Golang : Display a text file line by line with line number example


Instead of using cat or more commands to display a text file line by line. You want to display the file content line by line with a number for each line in a terminal. You also want to know how many total lines are there in the text file. How to do that?


Use this simple Golang program to display the text file content with line number on the right side.


 package main

 import (

 func main() {
 if len(os.Args) <= 1 {
 fmt.Printf("USAGE : %s <target_filename> \n", os.Args[0])

 fileName := os.Args[1]

 fileBytes, err := ioutil.ReadFile(fileName)

 if err != nil {

 lines := strings.Split(string(fileBytes), "\n")

 // remove the last item from the lines slice
 // which is empty
 lines = lines[:len(lines)-1]

 // len() function will count the total number of lines
 fmt.Println(fileName, "has a total of", len(lines), "lines")
 for i, line := range lines {
 // i = i + 1 // uncomment to start from 1 instead of 0
 fmt.Println(i, line)


Sample output:

$ ./countdisplaylines 123.txt

123.txt has a total of 3 lines

0 one

1 two

2 three

content of the 123.txt file:




  See also : Golang : Write multiple lines or divide string into multiple lines

By Adam Ng

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