Linux基础

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一、第一次写博客，希望大家多多包涵。如有不足，欢迎大佬们多多指点。纪念一下自己的学习经历。

二、Linux基础学习

查看LINUX系统版本

[root@centos7~]#cat /etc/centos-release
CentOS Linux release 7.5.1804 (Core) 

查看运行模式

[root@centos7~]#runlevel
N 5

init 0=poweroff=关机 init 6重启

查看主机名称

[root@centos7~]#hostname
centos7.5.localdomain

exit=logout=CTRL+D 退出

修改主机名为centos7.55.localdomain

[root@centos7sysconfig]#hostnamectl set-hostname centos7.55.localdomain
[root@centos7sysconfig]#hostname
centos7.55.localdomain

查看系统内核版本

[root@centos7sysconfig]#uname -r
3.10.0-862.el7.x86_64

读出的内核信息进行解释

[root@centos7sysconfig]#free -h
              total        used        free      shared  buff/cache   available
Mem:           1.0G        398M        274M        8.7M        359M        434M
Swap:          2.0G          0B        2.0G

[root@centos7sysconfig]#cat /proc/meminfo 
MemTotal:        1057372 kB
MemFree:          281416 kB
MemAvailable:     444388 kB
Buffers:            2092 kB
Cached:           282076 kB
SwapCached:            0 kB
Active:           328384 kB
Inactive:         244428 kB
Active(anon):     289568 kB
Inactive(anon):     8032 kB
Active(file):      38816 kB
Inactive(file):   236396 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:       2097148 kB
SwapFree:        2097148 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:        288772 kB
Mapped:            91648 kB
Shmem:              8956 kB
Slab:              83664 kB
SReclaimable:      31396 kB
SUnreclaim:        52268 kB
KernelStack:        7136 kB
PageTables:        22740 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     2625832 kB
Committed_AS:    1934240 kB
VmallocTotal:   34359738367 kB
VmallocUsed:      183508 kB
VmallocChunk:   34359310332 kB
HardwareCorrupted:     0 kB
AnonHugePages:     73728 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:       96128 kB
DirectMap2M:     1013760 kB
DirectMap1G:           0 kB

查看CPU

[root@centos7sysconfig]#lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                2
On-line CPU(s) list:   0,1
Thread(s) per core:    1
Core(s) per socket:    1
Socket(s):             2
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 94
Model name:            Intel(R) Core(TM) i5-6300HQ CPU @ 2.30GHz
Stepping:              3
CPU MHz:               2303.997
CPU max MHz:           0.0000
CPU min MHz:           0.0000
BogoMIPS:              4607.99
Hypervisor vendor:     VMware
Virtualization type:   full
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              6144K
NUMA node0 CPU(s):     0,1
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc aperfmperf eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch epb fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 invpcid rtm rdseed adx smap xsaveopt ibpb ibrs stibp dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp spec_ctrl intel_stibp

查看硬盘情况

[root@centos7sysconfig]#lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0  200G  0 disk 
├─sda1   8:1    0    1G  0 part /boot
├─sda2   8:2    0   50G  0 part /
├─sda3   8:3    0    2G  0 part [SWAP]
├─sda4   8:4    0    1K  0 part 
└─sda5   8:5    0   20G  0 part /data
sr0     11:0    1  8.8G  0 rom  

查看用户的UUID

[root@centos7sysconfig]#id -u root
0
[root@centos7sysconfig]#id -u zhang
1000

查看当前用户

[root@centos7sysconfig]#whoami
root

查看登录的主机

[root@centos7sysconfig]#who am i 
root     pts/0        2019-07-17 10:02 (192.168.13.1)

查看运行的程序

[root@centos7sysconfig]#w
 10:36:56 up 34 min,  1 user,  load average: 0.04, 0.04, 0.05
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
root     pts/0    192.168.13.1     10:02    0.00s  0.22s  0.03s w

查看当前系统使用的所有SHELL

[root@centos7sysconfig]#cat /etc/shells 
/bin/sh
/bin/bash
/sbin/nologin
/usr/bin/sh
/usr/bin/bash
/usr/sbin/nologin
/bin/tcsh
/bin/csh

查看当前使用的SHELL

[root@centos7sysconfig]#echo $SHELL
/bin/bash

修改当前SHELL为csh

[root@centos7sysconfig]#/bin/csh 
[root@centos7 sysconfig]# echo $SHELL
/bin/bash

查看当前所在的位置

[root@centos7~]#pwd
/root

修改提示符 1是高亮；5是闪烁；41是背景颜色；33是字体颜色。只是暂时保存，永久保存放在/etc/profile.d/env.sh

[root@centos7 ~]#PS1="\[\e[1;5;41;33m\][\u@\h \W]\\$\[\e[0m\]"

系统自动的以某一个账户登录，

vim /etc/gdm/custom.conf

如图添加相应代码，重新启动就可以实现。

# GDM configuration storage

[daemon]
AutomaticLoginEnable=true
AutomaticLogin=root
[security]

[xdmcp]

[chooser]

gedit 图形化

临时定义别名，如果需要永久生效，需要写在.bashrc（当前用户生效）/etc/bashrc(对所有用户生效)

[root@centos7~]#alias cdnet=‘cd /etc/sysconfig/network-scripts/‘
[root@centos7~]#cdnet
[root@centos7network-scripts]#

[root@centos7~]#vim .bashrc 
alias cdnet=‘cd /etc/sysconfig/network-scripts/‘

开机自动连接网络，打开/etc/sysconfig/network-scripts/ifcfg-ens33,把里面的ONBOOT=no,改为yes即可。

[root@centos7~]#cd /etc/sysconfig/network-scripts/
[root@centos7network-scripts]#ls
ifcfg-ens33  ifdown-ppp       ifup-ib      ifup-Team
ifcfg-lo     ifdown-routes    ifup-ippp    ifup-TeamPort
ifdown       ifdown-sit       ifup-ipv6    ifup-tunnel
ifdown-bnep  ifdown-Team      ifup-isdn    ifup-wireless
ifdown-eth   ifdown-TeamPort  ifup-plip    init.ipv6-global
ifdown-ib    ifdown-tunnel    ifup-plusb   network-functions
ifdown-ippp  ifup             ifup-post    network-functions-ipv6
ifdown-ipv6  ifup-aliases     ifup-ppp
ifdown-isdn  ifup-bnep        ifup-routes
ifdown-post  ifup-eth         ifup-sit
[root@centos7network-scripts]#vim ifcfg-ens33 

date常用，

[root@centos7~]#date +‘%F %T‘
2019-07-17 20:53:20

date -d ‘-1 day‘只是显示当天前一天的时间，并不真正的修改当前的时间；建一个以前一天时间为名称的.log文件

建在/data/下，一般定时备份时使用。

[root@centos7~]#touch /data/`date -d ‘-1 day‘ +%F`.log
[root@centos7~]#ls /data/
2019-07-16.log

新添加的硬盘显示不出来，可以访问echo ‘- - -‘> /sys/class/scsi_host/host2/scan

[root@centos7~]#lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0  200G  0 disk 
├─sda1   8:1    0    1G  0 part /boot
├─sda2   8:2    0  100G  0 part /
├─sda3   8:3    0    2G  0 part [SWAP]
├─sda4   8:4    0    1K  0 part 
└─sda5   8:5    0   50G  0 part /data
sr0     11:0    1   10G  0 rom  /run/media/root/CentOS 7 x86_64
[root@centos7~]#echo ‘- - -‘> /sys/class/scsi_host/host2/scan 
[root@centos7~]#lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0  200G  0 disk 
├─sda1   8:1    0    1G  0 part /boot
├─sda2   8:2    0  100G  0 part /
├─sda3   8:3    0    2G  0 part [SWAP]
├─sda4   8:4    0    1K  0 part 
└─sda5   8:5    0   50G  0 part /data
sdb      8:16   0   20G  0 disk 
sr0     11:0    1   10G  0 rom  /run/media/root/CentOS 7 x86_64

主机名示例.北京-亦庄-节点1-IP后2位-公司名称

bj-yz-k8s-node1-100-10.magedu.com

which --skip-alias可以取消别名查看

[root@centos7 dev]#which ls
alias ls=‘ls --color=auto‘
    /usr/bin/ls
[root@centos7 dev]#which --skip-alias ls
/usr/bin/ls

obase=2 在bc中，输入其他进制，输出2进制

inase=2 输入2进制，转化为10进制

centos7中mandb 建立whatis数据库，只能是root用户使用

centos6中makewhatis建立whatis数据库

查看所用的语言

[root@centos7 ~]#echo $LANG
en_US.UTF-8

在本机字符终端登录时，除显示原有信息外，再显示当前登录终端号，主机名和当前时间

root@centos7 ~]#vim /etc/issue
\S
time is \t
tty is \l
hostname is \n
Kernel \r on an \m

自动关机，并提示用户

[root@centos7 ~]#shutdown -t 072009552019 ;echo -e ‘\a‘;echo -e ‘\033[43;31;5m‘this computer is halt‘\033[0m‘
Shutdown scheduled for Sat 2019-07-20 09:44:44 CST, use ‘shutdown -c‘ to cancel.

this computer is halt
[root@centos7 ~]#
Broadcast message from root@centos7.6.localdomain (Sat 2019-07-20 09:43:44 CST):

The system is going down for power-off at Sat 2019-07-20 09:44:44 CST!

显示当前时间。+号和后面的中间不能有空格，否则不能执行。

[root@centos7 ~]#date  +‘%F %T‘
2019-07-20 09:50:18

显示前天是星期几

[root@centos7 ~]#date  -d ‘-2 day‘ +%A
Thursday

设置当前日期为2019-08-07 06:05:10

[root@centos7 ~]#date 080706052019.10
Wed Aug  7 06:05:10 CST 2019

enable 禁用内部命令

enable -n 解除内部命令

sz .bashrc 把Linux文件传到win上

hash -d uname 清楚uname的缓存

[root@centos7 data]#hexdump test.txt 
0000000 6261 3163 3332 000a                    
0000007
[root@centos7 data]#cat test.txt 
abc123

screen 的一些用法

建立一个新的会话
[root@centos7 data]#screen -S help
[detached from 8974.help]
查看所有的回话信息
[root@centos7 ~]#screen -ls
There is a screen on:
    8974.help   (Attached)
1 Socket in /var/run/screen/S-root.
加入第一个终端建立的screen回话
[root@centos7 ~]#screen -x help

Linux基础

标签：vpc   top   名称   flush   内核   config   kernel   nfs   which   

原文地址：https://blog.51cto.com/14451122/2421941