RHCE Official Training Notes---share

Lesson One:
1. Install local Yum source
#cd/ETC/YUM.REPOS.D
#wget Http://172.25.254.254/content/dvd.repo
#yum-y Install Tigervnc
#vncviewer 172.25.254.199
Password: redhat
2. Configure the IP address
#nmtui (config)
#172.25.254.0/24 (used after 100)
Lesson Two:
1. When the user is deleted, the owner of the original file will become the file identifier. That is, the UID of the user.
2. User group password, set up. Allows users to temporarily enter a group with a password to get group permissions
3. Users can delete, only look at the directory permissions, do not see the file permissions. All files are for one level only, and if there is a file under the directory and no permissions, it is not deleted.
#mkdir Root
#cd Root
#如果目录下还有文件, delete the file, depending on the permissions of the root file itself
If the directory has no files, deleting the files depends on the directory itself permissions.
4. When there is a conflict of authority, Uer>group>other
5.1) ': single quote, encounters any special characters as output.
2) "": double quotes, encountered any special characters are output, in addition to the following four cases
！ $  $()  `
6. Environment variable Priority
/etc/profile (Global environment variable)
~/.bash_profile (User environment variable)
~/.BASHRC (log in shell)
/ETC/BASHRC (Global user's Shell)

Lesson Three:
1, Tail-n +5/etc/passwd from the 5th line to the end of the file
2, Tail-f/var/log/* If you do not know that the service failed to start, you can use this.
3, Journalctl-x (R7) Check the newspaper wrong.
4, Grep-w precision Matching
5, Grep-r According to file content search
Grep-rn-w aaaa/etc/
6./etc/squid/squid.conf This file restricts network use
7. Back up a copy of Sed-i.bak when replacing
Sed-f file (write condition) filename

Lesson Four:
1, PTS/1 pseudo terminal
2. Tty1 Terminal
3. Tuning: Load 1 5 15 View high CPU usage
WA value: loiwait I/O occupies high. Hi: Hard Interrupt, si: Soft interrupt
4. Pidof: View the process number of a process.
Pgrep: View the process number of a process.
5, Signal 1,re-load 9 forced End Process 15 normal shutdown
6, write the script if in order to express the execution result failure, you can use exit 1, artificial assignment!
7, scheduled tasks, the system comes with a scheduled task, priority can be added 0 beginning,/etc/anacrontab if the task did not execute successfully, every 5 minutes check.
Run once per 5 s
#！ /bin/bash
While Trun
Do
Ls-l/etc
Sleep 5s
Done

Lesson Five:
1. IP link Show eth[x]
View interface Status
2. Locate-i ignoring case
3, Find-perm +222 Ugo can have write permission
find-perm-222
find-perm-002 other people have write permission
4.netstat-r Viewing routes

Lesson Six:
1, Rhel7 Systemctl
Systemctl Restart Network
Systemctl Enable
Systemctl Mask Network (next boot not up network)
Ln-s '/dev/null/etc/systemd/system
Systemctl Umask Network
2, rpm
Rpm-q--scripts vsftp
RPM--import Rpm-gpg-key-redhat-release
3. Yum
Yum whatprovides "/etc/minme.types"
Yum whatprovides "*/stem-config-kickstat"

This article from "intentions to create value, late coffee" blog, declined reprint!

RHCE Official Training Notes---share