Documentation ¶
Overview ¶
Package shell contains high-level features that use the syntax, expand, and interp packages under the hood.
Please note that this package uses POSIX Shell syntax. As such, path names on Windows need to use double backslashes or be within single quotes when given to functions like Fields. For example:
shell.Fields("echo /foo/bar") // on Unix-like shell.Fields("echo C:\\foo\\bar") // on Windows shell.Fields("echo 'C:\foo\bar'") // on Windows, with quotes
Index ¶
- func Expand(s string, env func(string) string) (string, error)
- func Fields(s string, env func(string) string) ([]string, error)
- func SourceFile(ctx context.Context, path string) (map[string]expand.Variable, error)
- func SourceNode(ctx context.Context, node syntax.Node) (map[string]expand.Variable, error)
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Expand ¶
Expand performs shell expansion on s as if it were within double quotes, using env to resolve variables. This includes parameter expansion, arithmetic expansion, and quote removal.
If env is nil, the current environment variables are used. Empty variables are treated as unset; to support variables which are set but empty, use the expand package directly.
Command subsitutions like $(echo foo) aren't supported to avoid running arbitrary code. To support those, use an interpreter with the expand package.
An error will be reported if the input string had invalid syntax.
Example ¶
package main import ( "fmt" "mvdan.cc/sh/shell" ) func main() { env := func(name string) string { switch name { case "HOME": return "/home/user" } return "" // leave the rest unset } out, _ := shell.Expand("No place like $HOME", env) fmt.Println(out) out, _ = shell.Expand("Some vars are ${missing:-awesome}", env) fmt.Println(out) out, _ = shell.Expand("Math is fun! $((12 * 34))", nil) fmt.Println(out) }
Output: No place like /home/user Some vars are awesome Math is fun! 408
func Fields ¶
Fields performs shell expansion on s as if it were a command's arguments, using env to resolve variables. It is similar to Expand, but includes brace expansion, tilde expansion, and globbing.
If env is nil, the current environment variables are used. Empty variables are treated as unset; to support variables which are set but empty, use the expand package directly.
An error will be reported if the input string had invalid syntax.
Example ¶
package main import ( "fmt" "mvdan.cc/sh/shell" ) func main() { env := func(name string) string { switch name { case "foo": return "bar baz" } return "" // leave the rest unset } out, _ := shell.Fields(`"many quoted" ' strings '`, env) fmt.Printf("%#v\n", out) out, _ = shell.Fields("unquoted $foo", env) fmt.Printf("%#v\n", out) out, _ = shell.Fields(`quoted "$foo"`, env) fmt.Printf("%#v\n", out) }
Output: []string{"many quoted", " strings "} []string{"unquoted", "bar", "baz"} []string{"quoted", "bar baz"}
func SourceFile ¶
SourceFile sources a shell file from disk and returns the variables declared in it. It is a convenience function that uses a default shell parser, parses a file from disk, and calls SourceNode.
This function should be used with caution, as it can interpret arbitrary code. Untrusted shell programs shoudn't be sourced outside of a sandbox environment.
Example ¶
package main import ( "context" "fmt" "io/ioutil" "os" "mvdan.cc/sh/shell" ) func main() { src := ` foo=abc foo+=012 if true; then bar=$(echo example_*.go) fi ` ioutil.WriteFile("f.sh", []byte(src), 0666) defer os.Remove("f.sh") vars, err := shell.SourceFile(context.TODO(), "f.sh") if err != nil { return } fmt.Println(len(vars)) fmt.Println("foo", vars["foo"]) fmt.Println("bar", vars["bar"]) }
Output: 2 foo abc012 bar example_test.go
func SourceNode ¶
SourceNode sources a shell program from a node and returns the variables declared in it. It accepts the same set of node types that interp/Runner.Run does.
This function should be used with caution, as it can interpret arbitrary code. Untrusted shell programs shoudn't be sourced outside of a sandbox environment.
Types ¶
This section is empty.