Linux 基础回顾及运行环境检查

网络检查：

ping www.163.com    #使用PING命令检查外网链接情况

查看当前网络运行环境

netstat -nr    #打印当前路由表

Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         10.75.119.1     0.0.0.0         UG        0 0          0 enp134s0f0
10.75.116.0     0.0.0.0         255.255.252.0   U         0 0          0 enp134s0f0
12.12.12.0      0.0.0.0         255.255.255.0   U         0 0          0 ib0
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 eno1
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 enp134s0f0
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 ib0
172.16.10.0     0.0.0.0         255.255.255.0   U         0 0          0 eno1
172.16.20.0     0.0.0.0         255.255.255.0   U         0 0          0 eno1

ifconfig    #显示当前内核网络接口的工作状态

eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.16.10.200  netmask 255.255.255.0  broadcast 172.16.10.255
        inet6 fe80::a94:efff:fe70:4eb3  prefixlen 64  scopeid 0x20<link>
        ether 08:94:ef:70:4e:b3  txqueuelen 1000  (Ethernet)
        RX packets 1582654868  bytes 305433476235 (284.4 GiB)
        RX errors 0  dropped 47810958  overruns 0  frame 0
        TX packets 190138297  bytes 34977293520 (32.5 GiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eno1:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.16.20.200  netmask 255.255.255.0  broadcast 172.16.20.255
        ether 08:94:ef:70:4e:b3  txqueuelen 1000  (Ethernet)

enp134s0f0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.75.119.206  netmask 255.255.252.0  broadcast 10.75.119.255
        inet6 fe80::a236:9fff:fe20:9fb8  prefixlen 64  scopeid 0x20<link>
        ether a0:36:9f:20:9f:b8  txqueuelen 1000  (Ethernet)
        RX packets 16110972352  bytes 17710866791280 (16.1 TiB)
        RX errors 0  dropped 47810919  overruns 0  frame 0
        TX packets 7315734650  bytes 3290896593864 (2.9 TiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

系统环境检查：

lsb_release -a     #列出当前系统及内核版本信息

LSB Version:    :core-4.1-amd64:core-4.1-noarch:cxx-4.1-amd64:cxx-4.1-noarch:desktop-4.1-amd64:desktop-4.1-noarch:languages-4.1-amd64:languages-4.1-noarch:printing-4.1-amd64:printing-4.1-noarch
Distributor ID: CentOS
Description:    CentOS Linux release 7.4.1708 (Core)
Release:        7.4.1708
Codename:       Core 

软件包安装检查：

Ubuntu系统:

apt list --installed    #查看所有安装的包

Debian系统:

dpkg-query -l    #查看所有安装的包

CentOS系统：

rpm -qa #查看所有安装的包
rpm -qa | grep ???  #查看???包是否在已安装列表并返回

Ubuntu软件源列表查看

cd /etc/apt/    #访问/etc/apt/ 文件夹
vi sources.list #查看目前的软件源列表
esc :q! #不保存退出 Ubuntu

软件源列表修改

可以使用如下命令：

sudo sed -i 's/archive.ubuntu.com/mirrors.ustc.edu.cn/g' /etc/apt/sources.list        #将默认的源地址[http://archive.ubuntu.com/](http://archive.ubuntu.com/) 替换为 [http://mirrors.ustc.edu.cn](http://mirrors.ustc.edu.cn/)
sudo apt-get update  

Linux环境变量查看/修改

环境变量的查看

按变量的生存周期来划分，Linux变量可分为两类：

1 永久的：需要修改配置文件，变量永久生效。

2 临时的：使用export命令声明即可，变量在关闭shell时失效。

nohup相关

nohup python -utry.py &>nohup.out&        #将屏幕输出实时加入nohup.out文件
tail -fn 50 nohup.out             #查看最近50行输出内容