如何为进程设置环境变量？

Question

从如何在Swift脚本中运行终端命令（例如xcodebuild）复制：

import Foundation

@discardableResult
func shell(_ args: String...) -> Int32 {
    let task = Process()
    task.launchPath = "/usr/bin/env"
    task.arguments = args
    task.launch()
    task.waitUntilExit()
    return task.terminationStatus
}

shell("ls")
shell("xcodebuild", "-workspace", "myApp.xcworkspace")

这看起来很整洁。我只是想知道如何为进程（这里命名为task）设置环境变量，比如$PWD。

---

我尝试了以下方法：

import Foundation

@discardableResult
func execCommand(_ args: String...) -> Int32 {
    let process = Process()
    process.launchPath = "/usr/bin/env"
    process.environment = ["PWD": "/Users"]
    if let env = process.environment {
        print(env["PWD"] ?? "Unknown")
    } else {
        print("Environment not available!")
    }
    process.arguments = args
    process.launch()
    process.waitUntilExit()
    return process.terminationStatus
}


execCommand("pwd")

然后这些行被打印出来：

/Users
/private/tmp/AppIcon.appiconset

显然，环境变量已经被设置了，但是对pwd命令没有任何影响。

---

另一种方法：

import Foundation

@discardableResult
func execCommand(_ args: String...) -> Int32 {
    let process = Process()
    process.launchPath = "/usr/bin/env"
    var environment = ProcessInfo.processInfo.environment
    environment["PWD"] = "/Users" //optionally set new vars, or overwrite old ones
    process.environment = environment
    if let env = process.environment {
        print(env["PWD"] ?? "Unknown")
    } else {
        print("Environment not available!")
    }
    process.arguments = args
    process.launch()
    process.waitUntilExit()
    return process.terminationStatus
}


execCommand("pwd")

很遗憾，结果和之前一样。

- qed

---

https://developer.apple.com/reference/foundation/process/1409412-environment - Alexander

你不应该把一个 Process 实例称为 task。NSTask 已经更名。 - Alexander

Answer 1

你刚刚设置了Process的environment变量为包含变量和值映射的[String: String]。

let process = Process()
// ...
process.environment = ["home": "/Users/foo"]

如果你想传递当前环境，可以这样做:

let process = Process()
// ...
let environment = ProcessInfo.processInfo.environment
environment["home"] = "/Users/foo" //optionally set new vars, or overwrite old ones
process.environment = environment

如果你想设置工作目录，那不是由环境变量决定的，而是通过"currentDirectoryPath"属性来确定的。参考链接：currentDirectoryPath property。

let process = Process()
// ...
process.currentDirectoryPath = "/Users"

- Alexander

---

这是什么意思？ - Alexander

我很快会发布一个例子。 - qed

@qed 工作目录不是从环境变量中获取的，而是从 process.currentDirectoryPath 中获取的。我即将修改我的答案以使其更加清晰。 - Alexander