Files

Advanced · Standard Library & I/O

Reading and writing files — everyday real-world I/O.

• files1 — whole-file I/O with os.WriteFile / os.ReadFile
• files2 — streaming line by line with bufio.Scanner

Resources

• Go by Example: Reading Files · Writing Files
• Go by Example: Line Filters
• pkg.go.dev: os · bufio

Exercises

files1 test

files1 — reading and writing files

Show hint

Whole-file I/O:

os.WriteFile(path, []byte(content), 0o644)
data, err := os.ReadFile(path); return string(data), err

Source

files2 test

files2 — reading line by line with bufio.Scanner

Show hint

Scan advances one line per call:

for scanner.Scan() { n++ }

Source