RHEL7 Basic Operations (view IP configuration, turn off the firewall, temporarily or permanently shut down selinux, common command Operations)

* rhel7的基本操作*

1. View IP Configuration
[Email protected] ~]# LS/ETC/SYSCONFIG/NETWORK-SCRIPTS/IFCFG-ENP0S25
/etc/sysconfig/network-scripts/ifcfg-enp0s25
View DNS Configuration
[Email protected] ~]# cat/etc/resolv.conf

Generated by NetworkManager

NameServer 114.114.114.114
viewing IP and Host binding information
[Email protected] ~]# cat/etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
:: 1 localhost localhost.localdomain localhost6 localhost6.localdomain6
View Host Name
[Email protected] ~]# Cat/etc/hostname
admin203

2, turn off the firewall, set the boot not to start
View status
[[email protected] ~]# systemctl status Firewalld.service
firewalld.service-firewalld-dynamic Firewall daemon
loaded:loaded (/usr/lib/systemd/system/firewalld.service; Enabled Vendor preset:enabled)
Active:active (running) since Tue 2018-09-11 09:47:40 CST; 1 day 5h ago
Main pid:698 (fire WALLD)
CGroup:/system.slice/firewalld.service
└─698/usr/bin/python-es/usr/sbin/firewalld--nofork--nopid

Sep 09:47:40 admin203 systemd[1]: Starting firewalld-dynamic Firewall daemon ...
Sep 09:47:40 admin203 systemd[1]: Started firewalld-dynamic firewall daemon.
Turn off firewall
[[email protected] ~]# systemctl stop firewalld
Turn on firewall
[[email protected] ~]# Systemctl Start FIREWALLD
Boot firewall automatically
[[email protected] ~]# systemctl enable FIREWALLD
Turn off firewall automatically
[email  protected] ~]# systemctl disable FIREWALLD
removed symlink/etc/systemd/system/ Dbus-org.fedoraproject.firewalld1.service.
removed symlink/etc/systemd/system/basic.target.wants/firewalld.service.

3. Temporarily and permanently close SELinux
View SELinux Run Status
[Email protected] ~]# Getenforce
Enforcing
Temporarily turn off SELinux and view the running status
[Email protected] ~]# Setenforce 0
[Email protected] ~]# Getenforce
Permissive
Temporarily turn on SELinux and view the running status
[Email protected] ~]# Setenforce 1
[Email protected] ~]# Getenforce
Enforcing
Permanently close selinux, change enforcing to disabled, save reboot
[Email protected] ~]# Vim/etc/selinux/config

This file controls the state of the SELinux on the system. Selinux= can take one of the these three Values:enforcing-selinux security policy is enforced.permissive-selinux prints WA Rnings instead of Enforcing.disabled-no SELinux policy is loaded.

Selinux=disabled

Selinuxtype= can take one of three, values:targeted-targeted processes is protected,minimum-modification of target Ed Policy. Only selected processes is Protected.mls-multi level Security protection.

selinuxtype=targeted

4. Basic command operation
To view the currently owned virtual terminal with TTY
[[email protected] ~]# TTY
/dev/pts/0
Distinguish internal and external commands with type, syntax: Type the command to detect
[[Email protected] ~]# type cat
Cat is hashed (/USR/BIN/CAT)
[[Email protected] ~]# type pwd
PWD is a shell builtin
View all shell types
[Email protected] ~]# Cat/etc/shells
/bin/sh
/bin/bash
/sbin/nologin
/usr/bin/sh
/usr/bin/bash
/usr/sbin/nologin
Take a look at the last character of each line of/etc/passwd
[Email protected] ~]# head-1/etc/passwd
Root:x:0:0:root:/root:/bin/bash
See which files are in the current directory
[[email protected] ~]# ls
Anaconda-ks.cfg Mima
[Email protected] ~]# LS/ETC/PASSWD
/etc/passwd
View file details such as creation time, creator, file read and Write permissions
[Email protected] ~]# ls-l/etc/passwd
-rw-r--r--. 1 root root 1118 Sep 22:24/etc/passwd
Summary of shortcut keys under Linux
Clear screen: ctrl+l
Exit: Ctrl+d
Search History Command: Ctr+r

View hardware Time
[[email protected] ~]# hwclock
Wed Sep 2018 04:20:15 PM CST-0.875517 seconds
View system time
[[EMA Il protected] ~]# date
Wed Sep 16:20:44 CST 2018
Modification Time
[[email protected] ~]# date-s "2018-9-12 15:2 "
Wed Sep 15:22:30 CST 2018
View full Date
[[email protected] ~]# date" +%f "
2018-09-12
View year last two digits
[[email protected] ~]# date "+%y"

View seconds/minute
[[email protected] ~]# date "+%m"
+
[email  protected] ~]# Date "+%h"

[[email protected] ~]# date "+%s"
Wuyi
View Month Day
[[email  Protected] ~]# Date "+%y-%m-%d"
2018-09-12
Use time to measure when a command is run
[[email protected] ~]# temporal ls
Anaconda-ks.cfg Mima

Real 0m0.002s
User 0m0.001s
SYS 0m0.001s
Help command man, view manual page or command description
Syntax: Man command
[[email protected] ~]# man CP
View the current default RunLevel
[Email protected] ~]# Systemctl Get-default
Multi-user.target
Set default to third boot level
[Email protected] ~]# Systemctl set-default multi-user.target
Removed Symlink/etc/systemd/system/default.target.
Created symlink from/etc/systemd/system/default.target To/usr/lib/systemd/system/multi-user.target.
Set default to fifth start level
[Email protected] ~]# Systemctl set-default graphical.target
Removed Symlink/etc/systemd/system/default.target.
Created symlink from/etc/systemd/system/default.target To/usr/lib/systemd/system/graphical.target.

RHEL7 Basic Operations (view IP configuration, turn off the firewall, temporarily or permanently shut down selinux, common command Operations)