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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package exec
import (
"os"
"strings"
)
func canExec(file string) bool {
d, err := os.Stat(file)
if err != nil {
return false
}
return d.IsRegular() && d.Permission()&0111 != 0
}
// LookPath searches for an executable binary named file
// in the directories named by the PATH environment variable.
// If file contains a slash, it is tried directly and the PATH is not consulted.
func LookPath(file string) (string, os.Error) {
// NOTE(rsc): I wish we could use the Plan 9 behavior here
// (only bypass the path if file begins with / or ./ or ../)
// but that would not match all the Unix shells.
if strings.Contains(file, "/") {
if canExec(file) {
return file, nil
}
return "", &os.PathError{"lookpath", file, os.ENOENT}
}
pathenv := os.Getenv("PATH")
for _, dir := range strings.Split(pathenv, ":", -1) {
if dir == "" {
// Unix shell semantics: path element "" means "."
dir = "."
}
if canExec(dir + "/" + file) {
return dir + "/" + file, nil
}
}
return "", &os.PathError{"lookpath", file, os.ENOENT}
}
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