如何grep从Objective-C Cocoa应用程序执行终端命令(如)？
你可以用NSTask.这是一个运行' /usr/bin/grep foo bar.txt' 的例子.
int pid = [[NSProcessInfo processInfo] processIdentifier]; NSPipe *pipe = [NSPipe pipe]; NSFileHandle *file = pipe.fileHandleForReading; NSTask *task = [[NSTask alloc] init]; task.launchPath = @"/usr/bin/grep"; task.arguments = @[@"foo", @"bar.txt"]; task.standardOutput = pipe; [task launch]; NSData *data = [file readDataToEndOfFile]; [file closeFile]; NSString *grepOutput = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding]; NSLog (@"grep returned:\n%@", grepOutput);
NSPipe并NSFileHandle用于重定向任务的标准输出.
有关从Objective-C应用程序中与操作系统交互的更多详细信息,您可以在Apple的开发中心上看到此文档:与操作系统交互.
编辑:包含NSLog问题的修复程序
如果您使用NSTask通过bash运行命令行实用程序,那么您需要包含此魔术行以保持NSLog正常工作:
//The magic line that keeps your log where it belongs task.standardOutput = pipe;
解释如下:https://web.archive.org/web/20141121094204/https://cocoadev.com/HowToPipeCommandsWithNSTask
本着共享的精神...这是我经常用来运行shell脚本的方法.您可以将脚本添加到产品包中(在构建的复制阶段),然后在运行时读取并运行脚本.注意:此代码在privateFrameworks子路径中查找脚本.警告:这可能会对部署的产品造成安全风险,但对于我们的内部开发,它是一种简单的方法来定制简单的东西(比如rsync到哪个主机......)而无需重新编译应用程序,只需编辑捆绑包中的shell脚本.
//------------------------------------------------------
-(void) runScript:(NSString*)scriptName
{
NSTask *task;
task = [[NSTask alloc] init];
[task setLaunchPath: @"/bin/sh"];
NSArray *arguments;
NSString* newpath = [NSString stringWithFormat:@"%@/%@",[[NSBundle mainBundle] privateFrameworksPath], scriptName];
NSLog(@"shell script path: %@",newpath);
arguments = [NSArray arrayWithObjects:newpath, nil];
[task setArguments: arguments];
NSPipe *pipe;
pipe = [NSPipe pipe];
[task setStandardOutput: pipe];
NSFileHandle *file;
file = [pipe fileHandleForReading];
[task launch];
NSData *data;
data = [file readDataToEndOfFile];
NSString *string;
string = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
NSLog (@"script returned:\n%@", string);
}
//------------------------------------------------------
编辑:包含NSLog问题的修复程序
如果您使用NSTask通过bash运行命令行实用程序,那么您需要包含此魔术行以保持NSLog正常工作:
//The magic line that keeps your log where it belongs [task setStandardInput:[NSPipe pipe]];
在上下文中:
NSPipe *pipe; pipe = [NSPipe pipe]; [task setStandardOutput: pipe]; //The magic line that keeps your log where it belongs [task setStandardInput:[NSPipe pipe]];
解释如下:http://www.cocoadev.com/index.pl？NSTask
肯特的文章给了我一个新的想法.这个runCommand方法不需要脚本文件,只需按行运行命令:
- (NSString *)runCommand:(NSString *)commandToRun
{
NSTask *task = [[NSTask alloc] init];
[task setLaunchPath:@"/bin/sh"];
NSArray *arguments = [NSArray arrayWithObjects:
@"-c" ,
[NSString stringWithFormat:@"%@", commandToRun],
nil];
NSLog(@"run command:%@", commandToRun);
[task setArguments:arguments];
NSPipe *pipe = [NSPipe pipe];
[task setStandardOutput:pipe];
NSFileHandle *file = [pipe fileHandleForReading];
[task launch];
NSData *data = [file readDataToEndOfFile];
NSString *output = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
return output;
}
您可以像这样使用此方法:
NSString *output = runCommand(@"ps -A | grep mysql");
Swift 3.0的变化:
NSPipe已重命名Pipe
NSTask已重命名Process
这是基于上面的墨水的Objective-C答案.他写了它作为一个类别上NSString-对于斯威夫特,它成为一个扩展的String.
extension String {
func runAsCommand() -> String {
let pipe = Pipe()
let task = Process()
task.launchPath = "/bin/sh"
task.arguments = ["-c", String(format:"%@", self)]
task.standardOutput = pipe
let file = pipe.fileHandleForReading
task.launch()
if let result = NSString(data: file.readDataToEndOfFile(), encoding: String.Encoding.utf8.rawValue) {
return result as String
}
else {
return "--- Error running command - Unable to initialize string from file data ---"
}
}
}
let input = "echo hello" let output = input.runAsCommand() print(output) // prints "hello"
要不就:
print("echo hello".runAsCommand()) // prints "hello"
@IBAction func toggleFinderShowAllFiles(_ sender: AnyObject) {
var newSetting = ""
let readDefaultsCommand = "defaults read com.apple.finder AppleShowAllFiles"
let oldSetting = readDefaultsCommand.runAsCommand()
// Note: the Command results are terminated with a newline character
if (oldSetting == "0\n") { newSetting = "1" }
else { newSetting = "0" }
let writeDefaultsCommand = "defaults write com.apple.finder AppleShowAllFiles \(newSetting) ; killall Finder"
_ = writeDefaultsCommand.runAsCommand()
}
请注意,Process结果为已读从Pipe是一个NSString对象.它可能是一个错误字符串,它也可以是一个空字符串,但它应该始终是一个NSString.
所以,只要它不是nil,结果就可以转换为Swift String并返回.
如果由于某种原因根本NSString无法从文件数据初始化,则该函数返回错误消息.该函数可能已被编写为返回一个可选项String?,但使用起来很难,并且不会起到有用的作用,因为它不太可能发生.
清除了最顶层答案中的代码,使其更具可读性,更少冗余,增加了单行方法的优点并制作成NSString类别
@interface NSString (ShellExecution) - (NSString*)runAsCommand; @end
执行:
@implementation NSString (ShellExecution)
- (NSString*)runAsCommand {
NSPipe* pipe = [NSPipe pipe];
NSTask* task = [[NSTask alloc] init];
[task setLaunchPath: @"/bin/sh"];
[task setArguments:@[@"-c", [NSString stringWithFormat:@"%@", self]]];
[task setStandardOutput:pipe];
NSFileHandle* file = [pipe fileHandleForReading];
[task launch];
return [[NSString alloc] initWithData:[file readDataToEndOfFile] encoding:NSUTF8StringEncoding];
}
@end
用法:
NSString* output = [@"echo hello" runAsCommand];
而且,如果你遇到与输出编码的问题:
// Had problems with `lsof` output and Japanese-named files, this fixed it NSString* output = [@"export LANG=en_US.UTF-8;echo hello" runAsCommand];
希望它对你和对我未来都有用.(你好!)
这里有一个例子斯威夫特利用的Pipe,Process和String
extension String {
func run() -> String? {
let pipe = Pipe()
let process = Process()
process.launchPath = "/bin/sh"
process.arguments = ["-c", self]
process.standardOutput = pipe
let fileHandle = pipe.fileHandleForReading
process.launch()
return String(data: fileHandle.readDataToEndOfFile(), encoding: .utf8)
}
}
用法:
let output = "echo hello".run()
fork,exec和wait应该工作,如果你不是真的在寻找Objective-C特定的方法.fork创建当前正在运行的程序的副本,exec用新的程序替换当前运行的程序,并wait等待子进程退出.例如(没有任何错误检查):
#include#include
pid_t p = fork();
if (p == 0) {
/* fork returns 0 in the child process. */
execl("/other/program/to/run", "/other/program/to/run", "foo", NULL);
} else {
/* fork returns the child's PID in the parent. */
int status;
wait(&status);
/* The child has exited, and status contains the way it exited. */
}
/* The child has run and exited by the time execution gets to here. */
还有系统,它运行命令,就好像你从shell的命令行输入命令一样.它更简单,但您对情况的控制较少.
我假设您正在使用Mac应用程序,因此这些链接是针对这些函数的Apple文档,但它们都是POSIX,所以您应该在任何符合POSIX的系统上使用它们.
还有一个很好的旧POSIX 系统("echo -en'\ 007'");
我写了这个"C"函数,因为它NSTask是令人讨厌的..
NSString * runCommand(NSString* c) {
NSString* outP; FILE *read_fp; char buffer[BUFSIZ + 1];
int chars_read; memset(buffer, '\0', sizeof(buffer));
read_fp = popen(c.UTF8String, "r");
if (read_fp != NULL) {
chars_read = fread(buffer, sizeof(char), BUFSIZ, read_fp);
if (chars_read > 0) outP = $UTF8(buffer);
pclose(read_fp);
}
return outP;
}
NSLog(@"%@", runCommand(@"ls -la /"));
total 16751
drwxrwxr-x+ 60 root wheel 2108 May 24 15:19 .
drwxrwxr-x+ 60 root wheel 2108 May 24 15:19 ..
…
哦,为了完整/明确......
#define $UTF8(A) ((NSString*)[NSS stringWithUTF8String:A])
多年以后,C对我来说仍然是一个令人眼花缭乱的混乱......并且对我纠正上述严重缺点的能力缺乏信心 - 我提供的唯一的橄榄枝是@ inket的答案,这是最简单的骨头,对于我的同伴纯粹主义者/诽谤者......
id _system(id cmd) {
return !cmd ? nil : ({ NSPipe* pipe; NSTask * task;
[task = NSTask.new setValuesForKeysWithDictionary:
@{ @"launchPath" : @"/bin/sh",
@"arguments" : @[@"-c", cmd],
@"standardOutput" : pipe = NSPipe.pipe}]; [task launch];
[NSString.alloc initWithData:
pipe.fileHandleForReading.readDataToEndOfFile
encoding:NSUTF8StringEncoding]; });
}
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