objective-c - NSTask 没有从用户的环境中获取 $PATH

Question

我不知道为什么这个方法返回一个空白字符串：

- (NSString *)installedGitLocation {
    NSString *launchPath = @"/usr/bin/which";

    // Set up the task
    NSTask *task = [[NSTask alloc] init];
    [task setLaunchPath:launchPath];
    NSArray *args = [NSArray arrayWithObject:@"git"];
    [task setArguments:args];

    // Set the output pipe.
    NSPipe *outPipe = [[NSPipe alloc] init];
    [task setStandardOutput:outPipe];

    [task launch];

    NSData *data = [[outPipe fileHandleForReading] readDataToEndOfFile];
    NSString *path = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];

    return path;
}

如果不是@"git"作为参数传递，而是通过，@"which"我会/usr/bin/which按预期返回。所以至少原理是有效的。

从终端

$ which which
$ /usr/bin/which
$
$ which git
$ /usr/local/git/bin/git

所以它在那里工作。

我能想到的唯一一件事which就是不要搜索我环境中的所有路径。

这真让我抓狂！有没有人有任何想法？

编辑： 看起来这是关于设置 NSTask 或用户的 shell（例如，~/.bashrc），以便 NSTask 可以看到正确的环境（$PATH）。

Answer 1

尝试，

    [task setLaunchPath:@"/bin/bash"];
    NSArray *args = [NSArray arrayWithObjects:@"-l",
                     @“-C”，
                     @"哪个 git",
                     零];
    [任务集参数：参数]；

This worked for me on Snow Leopard; I haven't tested on any other system. The -l (lowercase L) tells bash to "act as if it had been invoked as a login shell", and in the process it picked up my normal $PATH. This did not work for me if the launch path was set to /bit/sh, even with -l.

Answer 2

通过 NSTask 运行任务使用fork()并exec()实际运行任务。根本不涉及用户的交互式外壳。由于$PATH（总的来说）是一个 shell 概念，因此当您谈论以其他方式运行进程时，它并不适用。

Answer 3

运行程序时 /usr/local/git/bin 是否在 $PATH 中？我认为which只查看用户的 $PATH。

Answer 4

看看问题Find out location of an executable file in Cocoa。看起来基本问题是一样的。不幸的是，答案不是很好和整洁，但那里有一些有用的信息。

Answer 5

In Swift NSTask is replaced by Process but this is what it works for me:

let process = Process()
process.launchPath = "/bin/bash"
process.arguments = ["-l", "-c", "which git"]