package path

import "path"

Package path implements utility routines for manipulating slash-separated paths.

The path package should only be used for paths separated by forward slashes, such as the paths in URLs. This package does not deal with Windows paths with drive letters or backslashes; to manipulate operating system paths, use the path/filepath package.

Index

• Variables
• func Base(path string) string
• func Clean(path string) string
• func Dir(path string) string
• func Ext(path string) string
• func IsAbs(path string) bool
• func Join(elem ...string) string
• func Match(pattern, name string) (matched bool, err error)
• func Split(path string) (dir, file string)

Examples

• Base
• Clean
• Dir
• Ext
• IsAbs
• Join
• Match
• Split

Variables

var ErrBadPattern = errors.New("syntax error in pattern")

ErrBadPattern indicates a pattern was malformed.

Functions

func Base

func Base(path string) string

Base returns the last element of path. Trailing slashes are removed before extracting the last element. If the path is empty, Base returns ".". If the path consists entirely of slashes, Base returns "/".

package main

import (
	"fmt"
	"path"
)

func main() {
	fmt.Println(path.Base("/a/b"))
	fmt.Println(path.Base("/"))
	fmt.Println(path.Base(""))
}

b
/
.

func Clean

func Clean(path string) string

Clean returns the shortest path name equivalent to path by purely lexical processing. It applies the following rules iteratively until no further processing can be done:

1. Replace multiple slashes with a single slash.
2. Eliminate each . path name element (the current directory).
3. Eliminate each inner .. path name element (the parent directory) along with the non-.. element that precedes it.
4. Eliminate .. elements that begin a rooted path: that is, replace "/.." by "/" at the beginning of a path.

The returned path ends in a slash only if it is the root "/".

If the result of this process is an empty string, Clean returns the string ".".

See also Rob Pike, “Lexical File Names in Plan 9 or Getting Dot-Dot Right,” https://9p.io/sys/doc/lexnames.html

package main

import (
	"fmt"
	"path"
)

func main() {
	paths := []string{
		"a/c",
		"a//c",
		"a/c/.",
		"a/c/b/..",
		"/../a/c",
		"/../a/b/../././/c",
		"",
	}

	for _, p := range paths {
		fmt.Printf("Clean(%q) = %q\n", p, path.Clean(p))
	}

}

Clean("a/c") = "a/c"
Clean("a//c") = "a/c"
Clean("a/c/.") = "a/c"
Clean("a/c/b/..") = "a/c"
Clean("/../a/c") = "/a/c"
Clean("/../a/b/../././/c") = "/a/c"
Clean("") = "."

func Dir

func Dir(path string) string

Dir returns all but the last element of path, typically the path's directory. After dropping the final element using Split, the path is Cleaned and trailing slashes are removed. If the path is empty, Dir returns ".". If the path consists entirely of slashes followed by non-slash bytes, Dir returns a single slash. In any other case, the returned path does not end in a slash.

package main

import (
	"fmt"
	"path"
)

func main() {
	fmt.Println(path.Dir("/a/b/c"))
	fmt.Println(path.Dir("a/b/c"))
	fmt.Println(path.Dir("/a/"))
	fmt.Println(path.Dir("a/"))
	fmt.Println(path.Dir("/"))
	fmt.Println(path.Dir(""))
}

/a/b
a/b
/a
a
/
.

func Ext

func Ext(path string) string

Ext returns the file name extension used by path. The extension is the suffix beginning at the final dot in the final slash-separated element of path; it is empty if there is no dot.

package main

import (
	"fmt"
	"path"
)

func main() {
	fmt.Println(path.Ext("/a/b/c/bar.css"))
	fmt.Println(path.Ext("/"))
	fmt.Println(path.Ext(""))
}

.css

func IsAbs

func IsAbs(path string) bool

IsAbs reports whether the path is absolute.

package main

import (
	"fmt"
	"path"
)

func main() {
	fmt.Println(path.IsAbs("/dev/null"))
}

true

func Join

func Join(elem ...string) string

Join joins any number of path elements into a single path, separating them with slashes. Empty elements are ignored. The result is Cleaned. However, if the argument list is empty or all its elements are empty, Join returns an empty string.

package main

import (
	"fmt"
	"path"
)

func main() {
	fmt.Println(path.Join("a", "b", "c"))
	fmt.Println(path.Join("a", "b/c"))
	fmt.Println(path.Join("a/b", "c"))

	fmt.Println(path.Join("a/b", "../../../xyz"))

	fmt.Println(path.Join("", ""))
	fmt.Println(path.Join("a", ""))
	fmt.Println(path.Join("", "a"))

}

a/b/c
a/b/c
a/b/c
../xyz

a
a

func Match

func Match(pattern, name string) (matched bool, err error)

Match reports whether name matches the shell pattern. The pattern syntax is:

pattern:
	{ term }
term:
	'*'         matches any sequence of non-/ characters
	'?'         matches any single non-/ character
	'[' [ '^' ] { character-range } ']'
	            character class (must be non-empty)
	c           matches character c (c != '*', '?', '\\', '[')
	'\\' c      matches character c

character-range:
	c           matches character c (c != '\\', '-', ']')
	'\\' c      matches character c
	lo '-' hi   matches character c for lo <= c <= hi

Match requires pattern to match all of name, not just a substring. The only possible returned error is ErrBadPattern, when pattern is malformed.

package main

import (
	"fmt"
	"path"
)

func main() {
	fmt.Println(path.Match("abc", "abc"))
	fmt.Println(path.Match("a*", "abc"))
	fmt.Println(path.Match("a*/b", "a/c/b"))
}

true <nil>
true <nil>
false <nil>

func Split

func Split(path string) (dir, file string)

Split splits path immediately following the final slash, separating it into a directory and file name component. If there is no slash in path, Split returns an empty dir and file set to path. The returned values have the property that path = dir+file.

package main

import (
	"fmt"
	"path"
)

func main() {
	split := func(s string) {
		dir, file := path.Split(s)
		fmt.Printf("path.Split(%q) = dir: %q, file: %q\n", s, dir, file)
	}
	split("static/myfile.css")
	split("myfile.css")
	split("")
}

path.Split("static/myfile.css") = dir: "static/", file: "myfile.css"
path.Split("myfile.css") = dir: "", file: "myfile.css"
path.Split("") = dir: "", file: ""

Directories