File Reading and Writing Basics

In this lesson you will learn the basics of reading and writing files in Go, so a program can save and load text files. This is for anyone searching for "Go file read write how to use".

os.WriteFile writes to a file and os.ReadFile reads one back. Saving configuration files and logs makes this a basic operation you will use often.

The sample code saves the contents of a note with os.WriteFile("memo.txt", []byte(...), 0644), then immediately reads the same file back with os.ReadFile("memo.txt") and prints it. Notice that the 0644 is the file's permission bits.

A common stumbling block for beginners is ignoring the error that comes back. Checking it rather than discarding it is the Go habit that makes file handling robust - checking what os.ReadFile returns lets you respond properly when the file is missing.

In real-world development you can also combine file operations with goroutines when you want them to run concurrently.