nodejs实用代码段（三）

1.获取并改变当前程序的目录

console.log("now dir is:"+process.cwd());process.chdir('/home/shiyanlou/wangyiyun');console.log("now dir is:"+process.cwd());

chdir 里的参数要是完整路径

2.查看系统相应信息

console.log(process.pid);console.info();console.log(process.title);console.info();console.log(process.version);console.log(process.versions);

process.version 是版本号 process.versions是版本属性  得到一个json对象

console.log(process.config);console.info();console.log(process.execPath);console.info();console.log(process.argv);

config 是nodejs的配置信息 也是一个json对象

execPath 是当前进程的可执行文件的绝对路径

argv 得到命令行参数数组

console.log(process.platform);console.info();console.log(process.arch);console.info();console.log(process.env);

第一个打印的是平台 linux windows

第二个是cpu架构信息 x64

第三个是shell里面各种有用的环境变量的地址

process.stdout.write("字符串");标准输出流  

process.stderr.write();标准错误流

process.stderr.write()标准输入流

process.kill

process.on('SIGHUP',function(){console.log('Got SIGHUP signal.');});setTimeout(function(){console.log('Exiting');process.exit(0);console.info("has aleady kill "+proecess.pid);},1000);process.kill(process.pid,'SIGHUP');

process的异步操作模块

console.time('startB');console.log('start-setTimeout');setTimeout(function(){console.log('nextTick callback 2');},0);console.log('scheduled-setTimeout');console.timeEnd('startB');console.time('startA');console.log('start-nextTick');process.nextTick(function(){console.log('nextTick callback 1');});console.log('scheduled-nextTick');console.timeEnd('startA');console.info();

这里面 process.nextTick()与setTimeout()一样完成了异步操作 但是前者几乎没有阻塞 效率高于后者