To read an entire file in Golang, you can use the “ReadFile()” function from the “ioutil/os” package. This function reads the entire file content into a byte slice, and then you can use the “string()” function to read the file content as a string.
package main
import (
"fmt"
"io/ioutil"
"log"
)
func main() {
data, err := ioutil.ReadFile("data.txt")
if err != nil {
log.Fatal(err)
}
// Print the contents of the file
fmt.Println(string(data))
}
Output
This is a text file
The file is read line by line
Hello World
The ioutil.ReadFile() function reads an entire file into memory as a byte slice.
In this example, we used the ioutil.ReadFile() function to read the contents of the file “data.txt” into the data variable.
If there’s an error while reading the file, you can handle it using the log.Fatal() function to print the error message and exit the program.
Finally, we used the fmt.Println() function to print the file’s contents as a string.
Note: The ioutil.ReadFile() function is unsuitable for reading large files since it simultaneously loads the entire file into memory. If you need to read a large file, you should use a buffered reader to read the file in chunks.

Krunal Lathiya is a seasoned Computer Science expert with over eight years in the tech industry. He boasts deep knowledge in Data Science and Machine Learning. Versed in Python, JavaScript, PHP, R, and Golang. Skilled in frameworks like Angular and React and platforms such as Node.js. His expertise spans both front-end and back-end development. His proficiency in the Python language stands as a testament to his versatility and commitment to the craft.