stderr

Right now I'm using exec to redirect stderr to an error log with exec 2>> ${errorLog} The only downside is that I have to start each run with a timestamp since exec just pushes the text straight into the log file. Is there a way to redirect stderr but allow me to append text to it, such as a time stamp? This is very interesting. I've asked a guy who knows bash quite well, and he told me this way: foo() { while IFS='' read -r line; do echo "$(date) $line" >> file.txt; done; }; First, that creates a function reading one line of raw input from stdin, while the assignment to IFS makes it doesn't

标准I/O与管道 标准输入和输出 读入数据：Input 输出数据：Output Linux给程序提供三种I/O设备 标准输入（STDIN）－0 默认接受来自键盘的输入 标准输出（STDOUT）－1 默认输出到终端窗口 标准错误（STDERR）－2 默认输出到终端窗口 I/O重定向：改变默认位置 把输出和错误重新定向到文件 STDOUT和STDERR可以被重定向到文件 命令 ~ 操作符号 ~ 文件名 支持的操作符号包括： 把STDOUT重定向到文件> 2> 把STDERR重定向到文件 &> 把所有输出重定向到文件 使用>文件内容会被覆盖 set -C 禁止将内容覆盖已有文件,但可追加 使用>| file 强制覆盖 set +C 允许覆盖 使用>>原有内容基础上，追加内容 把输出和错误重新定向到文件 2> 覆盖重定向错误输出数据流 2>> 追加重定向错误输出数据流 标准输出和错误输出各自定向至不同位置 COMMAND > /path/to/file.out 2> /path/to/error.out 合并标准输出和错误输出为同一个数据流进行重定向 &> 覆盖重定向 &>> 追加重定向 COMMAND > /path/to/file.out 2>&1 （顺序很重要） COMMAND >> /path/to/file.out 2>&1 ()：合并多个程序的STDOUT ( cal 2007

Reading the man pages and some code did not really help me in understanding the difference between - or better, when I should use - perror("...") or fprintf(stderr, "...") . Jason Calling perror will give you the interpreted value of errno , which is a thread-local error value written to by POSIX syscalls (i.e., every thread has it's own value for errno ). For instance, if you made a call to open() , and there was an error generated (i.e., it returned -1 ), you could then call perror immediately afterwards to see what the actual error was. Keep in mind that if you call other syscalls in the

The program I am making is designed to be run unattended, because of this I have redirected the stdout and stderr streams to a log file. While this works without any problems, while I am still making and debugging the software I would like it to show on the screen as well. Is this possible? To redirect the streams I have used System.setErr(logWriter); System.setOut(logWriter); Thanks. a bit crude perhaps, but you could try this: private static final isDebugMode = true; ... if (!isDebugMode) { System.setErr(logWriter); System.setOut(logWriter); } Alternatively you could write your own

Docker容器日志分为2类： Docker引擎日志（Docker本身运行的日志）。 容器日志，各个容器内产生的日志。 Docker引擎日志 Centos系统下Docker引擎log一般给systemd管理，可通过 journalctl -u docker.service 命令查看。 容器日志 一、查看日志命令 docker logs 容器ID 显示当前运行容器的log，输出Linux下的STDOUT（标准输出）、STDERR（标准错误输出），docker logs 显示的内容包含STDOUT和STDERR。生产环境中，如果应用输出到我们自己的日志文件里，使用docker logs一般收集不到太多重要信息，大多有用log在容器内部。 docker logs 容器ID 或 -f 参数 实施查看log，类似Linux的tail -f。如： [root@docker-qa logs]# docker ps |grep part ed9e7d9df4b1 b2b-partner-img/b2b-partner-test "/bin/sh -c 'java ..." 45 minutes ago Up 45 minutes 0.0.0.0:8081->8081/tcp b2b-partner-test-container [root@docker-qa logs]# [root@docker

1 ''' 2 远程执行cmd命令程序 3 如果不使用struct模块，ipconfig等会返回长数据的命令会发生黏包现象 4 ''' 5 import socket 6 import struct 7 8 sk = socket.socket() 9 sk.bind(("127.0.0.1", 8080)) 10 sk.listen() 11 conn, addr = sk.accept() 12 while True: 13 cmd = input(">>>") 14 if cmd == "q": 15 conn.send(b"q") 16 break 17 conn.send(bytes(cmd,encoding="gbk")) 18 # windows系统的命令行的编码格式是GBK所以要进行GBK转码 19 num = conn.recv(4) 20 # 接收返回数据的长度 21 num = int(struct.unpack("i",num)[0]) 22 # 将接收的bytes类型的struct转换的数字解码，因为返回的是元组所以取元组的第一个，并且下面要用的类型是整数型，转换成int类型 23 print(conn.recv(num).decode("gbk")) 24 # 接收上面传进来大小的数据，解码gbk，打印 25 # 发送多少接收多少就不会产生黏包现象了

链接+循环 通信 服务端常驻 server端 import socket phone=socket.socket()#买手机 phone.bind(('127.0.0.1',6666))#绑卡 phone.listen(5)#设置连接数一个连接加5个等待 缓存池 while 1: conn,addr=phone.accept() print(f'用户{addr}来了') while 1: try: from_client_data=conn.recv(1024) if from_client_data.decode('utf-8')=='Q': print('正常断开') break print(f'来自客户端{addr}消息{from_client_data.decode("utf-8")}') to_client_data=input('>>>>>>>') conn.send(to_client_data.encode('utf-8')) except Exception: break conn.close() phone.close() client端 # 自己的 import socket phone=socket.socket() phone.connect(('127.0.0.1',6666)) while 1: to_server_data=input('>>>>>

This question already has an answer here: Confused about stdin, stdout and stderr? 10 answers I'm trying to understand stdin stdout and stderr . I see them used in people's code all the time and I can't understand exactly what they are. I am assuming that they have something to do with input/output but have been searching for an explanation online and can't find one. Does anybody know of a good link with an explanation or if it is simple enough to explain it would be a great help to me. Since I am learning Python 3, examples in that would be helpful. sys.stdin sys.stdout sys.stderr File

I'd like to both capture and display the output of a process that I invoke through Python's subprocess. I thought I could just pass my file-like object as named parameter stdout and stderr I can see that it accesses the fileno attribute - so it is doing something with the object. However, the write() method is never invoked. Is my approach completely off or am I just missing something? class Process(object): class StreamWrapper(object): def __init__(self, stream): self._stream = stream self._buffer = [] def _print(self, msg): print repr(self), msg def __getattr__(self, name): if not name in [