Linux

Can't find process listed by `jobs` command

由 不羁岁月 提交于 2021-02-19 05:34:33
问题 I am using jobs command to control the number of compute-intensive processes. I want to not run more than max_cnt processes at a time, and stop only when all the processes have stopped. I use below bash script to accomplish this. However, this code always lists one process as running even after everything has executed and stopped. Moreover, I can't find that process listed in htop 's list of processes. What should I do or where should I look for that process that is listed by the result of

Detect keypress in console application?

由 旧巷老猫 提交于 2021-02-19 05:31:59
问题 I need to detect a keypress in a console application, without prompting the user. Basically, my app is normally a daemon that listens to a special input device, but i need to simulate it on a dev box using the keyboard in interactive mode. How can I do this? - Im on a Linux system. 回答1: If you can't block while waiting for input, then you can use e.g. select to check if the STDIN_FILENO file descriptor is ready for reading, and if it is then you can use normal input functions ( scanf , fgets

Detect keypress in console application?

由 血红的双手。 提交于 2021-02-19 05:31:35
问题 I need to detect a keypress in a console application, without prompting the user. Basically, my app is normally a daemon that listens to a special input device, but i need to simulate it on a dev box using the keyboard in interactive mode. How can I do this? - Im on a Linux system. 回答1: If you can't block while waiting for input, then you can use e.g. select to check if the STDIN_FILENO file descriptor is ready for reading, and if it is then you can use normal input functions ( scanf , fgets

Detect keypress in console application?

由 假如想象 提交于 2021-02-19 05:31:08
问题 I need to detect a keypress in a console application, without prompting the user. Basically, my app is normally a daemon that listens to a special input device, but i need to simulate it on a dev box using the keyboard in interactive mode. How can I do this? - Im on a Linux system. 回答1: If you can't block while waiting for input, then you can use e.g. select to check if the STDIN_FILENO file descriptor is ready for reading, and if it is then you can use normal input functions ( scanf , fgets

How to store multiple lines of command output to a variable using JSch

由 安稳与你 提交于 2021-02-19 05:30:30
问题 So, I have a nice bit of code (that I'm struggling to understand), that allows me to send a command to my server, and get one line of response. The code works, but I would like to get multiple lines back from the server. The main class is: JSch jSch = new JSch(); MyUserInfo ui = new MyUserInfo(); String Return = "Error"; try { String host = "Username@HostName"; String user = host.substring(0, host.indexOf('@')); host = host.substring(host.indexOf('@') + 1); Session rebootsession = jSch

查询linux发行版本号方法总结

由 北城余情 提交于 2021-02-19 05:17:17
了解Linux发行版本的版本号是一项非常重要的事情，大多数软件对系统的版本都有要求，发行版本号与软件不匹配，软件将无法安装或者无法使用.这边集合市面上流行的 Linux 发行版本版本号查询方法.有了这边文章，老板再也不担心我装错软件了呢 1. 发行版本号查询 Debian版本查询: # cat /etc/debian_version 5.0.7 # cat /etc/issue Debian GNU/Linux 5.0 \n \l Ubuntu版本查询: # cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=10.04 DISTRIB_CODENAME=lucid DISTRIB_DESCRIPTION="Ubuntu 10.04.4 LTS" # cat /etc/issue Ubuntu 10.04.4 LTS \n \l CentOS版本查询: # cat /etc/*-release CentOS release 6.4 (Final) CentOS release 6.4 (Final) CentOS release 6.4 (Final) RedHat版本查询: # cat /etc/redhat-release Red Hat Enterprise Linux Server release 6.0

linux 常用命令总结

由 北城以北 提交于 2021-02-19 05:02:12
新手非常有用的20个命令 1. ls命令 ls命令是列出目录内容(List Directory Contents)的意思。运行它就是列出文件夹里的内容，可能是文件也可能是文件夹。 “ls -l”命令已详情模式(long listing fashion)列出文件夹的内容。 “ls -a”命令会列出文件夹里的所有内容，包括以”.”开头的隐藏文件。 2. lsblk命令 “lsblk”就是列出块设备。除了RAM外，以标准的树状输出格式，整齐地显示块设备。 “lsblk -l”命令以列表格式显示块设备(而不是树状格式)。 3. md5sum命令 “md5sum”就是计算和检验MD5信息签名。md5 checksum(通常叫做哈希)使用匹配或者验证文件的文件的完整性，因为文件可能因为传输错误，磁盘错误或者无恶意的干扰等原因而发生改变。 root@tecmint:~# md5sum teamviewer_linux.deb 47790ed345a7b7970fc1f2ac50c97002 teamviewer_linux.deb 注意：用户可以使用官方提供的和md5sum生成签名信息匹对以此检测文件是否改变。Md5sum没有sha1sum安全，这点我们稍后讨论。 4. dd命令 “dd”命令代表了转换和复制文件。可以用来转换和复制文件，大多数时间是用来复制iso文件(或任何其它文件

nslookup详解(name server lookup)( 域名查询)

由 自作多情 提交于 2021-02-19 04:43:04
nslookup详解(name server lookup)( 域名查询) 一、总结 1、 爬虫倒是很方便拿到页面数据： a、网页的页面源码我们可以轻松获得 b、比如cnsd博客，文章的正文内容全部放在<article></article>当中，所以非常好获取，此时我们获取的是html的页面 c、html的数据自带格式，所以直接放到数据库即可，因为数据库里面存的也就是html数据，要显示的话直接把这部分数据放到页面上面来即可 2、 nslookup ：(name server lookup)( 域名查询) 二、nslookup详解(name server lookup)( 域名查询) nslookup可以指定查询的类型，可以查到DNS记录的生存时间还可以指定使用哪个 DNS服务器 进行解释。在已安装 TCP/IP协议 的电脑上面均可以使用这个命令。主要用来诊断 域名系统 (DNS) 基础结构的信息。Nslookup(name server lookup)( 域名查询 ):是一个用于查询 Internet 域名 信息或诊断DNS 服务器问题的工具. nslookup是 一个程序的名字 ，这个程序让因特网服务器管理员或任何的计算机用户 输入一个主机名（举例来说，“whatis.com.cn”）并发现相应的IP地址 。它也会 相反的名字查找为一个你指定的 IP 住址找出主机名 。 举例

How to find owner socket of sk_buff in Linux kernel?

由 时光毁灭记忆、已成空白 提交于 2021-02-19 04:41:49
问题 I'm trying to find the owner socket of an sk_buff instance, say, skb . My ultimate goal is to find a specific TCP option and somehow let the user space application to know. I plan to set a socket option when I find the TCP option and let the user space app to call getsockopt() . Therefore I need to know the ownership between sk_buff and sock . I find there is a field in sk_buff: struct sock *sk; However, when I try to retrieve this field at tcp_parse_options in tcp_input.c , I always get skb-

Linux基础命令---nslookup查询域名工具

由 荒凉一梦 提交于 2021-02-19 04:41:13
nslookup nslookup是一个查询DNS域名的工具，它有交互和非交互两种工作模式。 此命令的适用范围：RedHat、RHEL、Ubuntu、CentOS、Fedora。 1 、语法 nslookup [-option] [name | -] [server] 2 、进入交互模式之后有如下命令 命令 说明 host 查询host的信息 server domain 改变服务器 exit 退出 set keyword = value 设置指定属性 all，打印所有的属性 domain=name 设置查询的名字 port=value 改变服务器端口 type=value 改变查询的类型 timeout=number 设置等待超时 class={IN | CH | HS | ANY} 3 、实例 1）非交互模式查询 [root@localhost ~]# nslookup www.baidu.com Server: 172.20.10.1 Address: 172.20.10.1#53 Non-authoritative answer: www.baidu.com canonical name = www.a.shifen.com. Name: www.a.shifen.com Address: 111.13.100.91 Name: www.a.shifen.com
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