golangHow to overwrite content in file if it exists
package main
import (
"os"
)
func main() {
f, _ := os.OpenFile("/tmp/go.txt", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
defer f.Close()
f.WriteString("new content\n")
}ctrl + cpackage maindefault package declaration | "os"include operating-system level library |
func main() {declare | os.OpenFileopens file handler |
/tmp/go.txtpath to file to open | os.O_APPEND|os.O_CREATE|os.O_WRONLYpermissions used to append to file |
0644file permissions to set | defer f.Close()deferred file handler close |
WriteStringwrites string to a given file | |
Usage example
package main
import (
"fmt"
"os"
)
func main() {
f, _ := os.OpenFile("/tmp/go.txt", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
defer f.Close()
f.WriteString("new content\n")
t, _ := os.ReadFile("/tmp/go.txt")
fmt.Println(string(t))
}output
new content