Read a file (stdin) line by line

• Read from file
• Read from stdin
• Read from any stream

Read from file

Use a bufio.Scanner to read a file line by line.

file, err := os.Open("file.txt")
if err != nil {
	log.Fatal(err)
}
defer file.Close()

scanner := bufio.NewScanner(file)
for scanner.Scan() {
	fmt.Println(scanner.Text())
}

if err := scanner.Err(); err != nil {
	log.Fatal(err)
}

Read from stdin

Use os.Stdin to read from the standard input stream.

scanner := bufio.NewScanner(os.Stdin)
for scanner.Scan() {
	fmt.Println(scanner.Text())
}

if err := scanner.Err(); err != nil {
	log.Println(err)
}

Read from any stream

A bufio.Scanner can read from any stream of bytes, as long as it implements the io.Reader interface. See How to use the io.Reader interface.

Further reading

For more advanced scanning, see the examples in the bufio.Scanner documentation.