File Paths in Go
The filepath package provides functions to parse and construct file paths in a way that is portable between operating systems; dir/file on Linux vs. dir\file on Windows, for example.
package main
import (
"fmt"
"path/filepath"
"strings"
)
func main() {
// Join should be used to construct paths in a portable way.
// It takes any number of arguments and constructs a hierarchical path from them.
p := filepath.Join("dir1", "dir2", "filename")
fmt.Println("p:", p)
// You should always use Join instead of concatenating /s or \s manually.
// In addition to providing portability, Join will also normalize paths by
// removing superfluous separators and directory changes.
fmt.Println(filepath.Join("dir1//", "filename"))
fmt.Println(filepath.Join("dir1/../dir1", "filename"))
// Dir and Base can be used to split a path to the directory and the file.
// Alternatively, Split will return both in the same call.
fmt.Println("Dir(p):", filepath.Dir(p))
fmt.Println("Base(p):", filepath.Base(p))
// We can check whether a path is absolute.
fmt.Println(filepath.IsAbs("dir/file"))
fmt.Println(filepath.IsAbs("/dir/file"))
filename := "config.json"
// Some file names have extensions following a dot.
// We can split the extension out of such names with Ext.
ext := filepath.Ext(filename)
fmt.Println(ext)
// To find the file’s name with the extension removed, use strings.TrimSuffix.
fmt.Println(strings.TrimSuffix(filename, ext))
// Rel finds a relative path between a base and a target.
// It returns an error if the target cannot be made relative to base.
rel, err := filepath.Rel("a/b", "a/b/t/file")
if err != nil {
panic(err)
}
fmt.Println(rel)
rel, err = filepath.Rel("a/b", "a/c/t/file")
if err != nil {
panic(err)
}
fmt.Println(rel)
}