目标C版本的unix"finger"命令

Question

我正在尝试检查自上次登录我的Cocoa应用程序以来的时间.我想这样做而不必做这样的事情:

NSTask *task;
task = [[NSTask alloc] init];
[task setLaunchPath: @"/usr/bin/finger"];

NSArray *arguments;
arguments = [NSArray arrayWithObject: NSUserName()];
[task setArguments: arguments];

NSPipe *pipe;
pipe = [NSPipe pipe];
[task setStandardOutput: pipe];

NSFileHandle *file;
file = [pipe fileHandleForReading];

[task launch];

NSData *data;
data = [file readDataToEndOfFile];

NSString *stringData = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
NSLog (@"%@", stringData);

例如,Unix whoami命令具有NSUserNameObjective C等效项.

Answer 1

这是一个非常有趣的问题!谢谢你的询问.:)

至于答案,我去了,找到了源代码,finger并提出了以下内容:

#import <utmpx.h>

struct utmpx *user;
setutxent();
while ((user = getutxent()) != NULL) {
    if (user->ut_type == USER_PROCESS) {
        time_t loggedIn = user->ut_tv.tv_sec;
        NSDate * d = [NSDate dateWithTimeIntervalSince1970:loggedIn];
        NSLog(@"%s logged in at %@", user->ut_user, d);
    }
}
endutxent();

在我的电脑上,这个日志:

dave logged in at 2010-12-06 09:59:13 -0800
dave logged in at 2010-12-13 19:14:20 -0800

这匹配finger dave终端的输出:

Login: dave                     Name: Dave DeLong
Directory: /Users/dave                  Shell: /bin/bash
On since Mon Dec  6 09:59 (PST) on console, idle 7 days 9:18 (messages off)
On since Mon Dec 13 19:14 (PST) on ttys000
On since Thu Dec  9 17:21 (PST) on ttys001 (messages off)