英文:
Go: strange results when using strings with exec.Command
问题
我有一个处理Linux CLI命令及其参数的Go函数：
func cmd(cmd string, args ...string) ([]byte, error) {
path, err := exec.Command("/usr/bin/which", cmd).Output()
if err != nil {
return []byte(""), err
}
response, err := exec.Command(string(path), args...).Output()
if err != nil {
response = []byte("Unknown")
}
return response, err
}
它被以下代码调用：
func main() {
uname, err := cmd("uname", "-a")
fmt.Println(string(uname))
}
"which"命令返回正确的二进制文件路径，但是当它尝试使用动态路径运行第二个exec命令时，返回的结果总是：
fork/exec /usr/bin/uname: no such file or directory
exit status 1
然而，如果第二个exec命令是硬编码的，一切都按预期工作并打印出uname的结果：
response, err := exec.Command("/usr/bin/uname", args...).Output()
我是否对exec和字符串的行为有所遗漏？
谢谢。
英文:
I have a Go function that processes Linux CLI commands and their arguments:
func cmd(cmd string, args ...string) ([]byte, error) {
path, err := exec.Command("/usr/bin/which", cmd).Output()
if err != nil {
return []byte(""), err
}
response, err := exec.Command(string(path), args...).Output()
if err != nil {
response = []byte("Unknown")
}
return response, err
}
Which is called by the following:
func main() {
uname, err := cmd("uname", "-a")
fmt.Println(string(uname))
}
The "which" command returns the correct path to the binary but when it tries to run the second exec command with a dynamic path the return is always:
fork/exec /usr/bin/uname
: no such file or directory
exit status 1
Yet if the second exec command is hardcoded, everything works as expected and prints the uname:
response, err := exec.Command("/usr/bin/uname", args...).Output()
Am I missing something about how exec and strings behave?
Thanks
答案1
得分: 5
which命令在可执行文件的名称后打印一个换行符。path变量被设置为"/usr/bin/uname\n"。这个路径下没有可执行文件。额外的换行符在错误消息中可见（即在冒号之前的换行符）。
修剪换行符后，可以得到正确的可执行文件名称：
response, err := exec.Command(strings.TrimSuffix(string(path), "\n"), args...).Output()
英文:
The which command prints a newline following the name of the executable. The path variable is set to "/usr/bin/uname\n". There is no executable with this path. The extra newline is visible in the error message (the newline just before the ":").
Trim the newline suffix to get the correct name of the executable:
response, err := exec.Command(strings.TrimSuffix(string(path), "\n"), args...).Output()
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