RedHat/CentOs Commands for administrative works
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This document provides a list of keyboard shortcuts and Linux commands. Some key shortcuts include Ctrl+Alt+Backspace to kill the X session, Ctrl+Alt+Delete to shut down from a non-graphical shell, and Alt+Tab to switch tasks. Common commands are ls to list files, cd to change directories, grep to search files, and sudo to run commands with admin privileges. System administration commands include useradd to add users, chown to change file ownership, and top to view running processes.
![IDB-BISEW
MD. SHIHAB HOSSAIN
A simple keyboard shortcuts layout
1. [Ctrl] + [Alt] + [Backspace] = kills your current X session.
2. [Ctrl] + [Alt] + [Delete] = From a non-graphical shell prompt, shuts down your Red Hat
Enterprise Linux system.
3. [Ctrl] + [Alt] + [Fn] = switches screens. [Ctrl]+[Alt] + one of the function keys displays
an available screen. By default, [F1] through [F6] are text-mode shell prompt screens and
[F7] is the graphical desktop screen.
4. [Alt] + [Tab] = switches tasks in a graphical desktop environment.
5. [Ctrl] + [a] = moves cursor to the beginning of a line.
6. [Ctrl] + [d] = logout of (and close) shell prompt. [Ctrl] + [e] = moves cursor to end of a
line. This works in most text editors and in the URL field in Mozilla.
7. [Ctrl] + [l] = clears the terminal
8.
9. [Ctrl] + [u] = clears the current line.
a. .
10. [Middle Mouse Button] = pastes highlighted text.
11. [Tab] = command autocomplete
12. [Up] and [Down] Arrow = shows command history.
13. clear = clears the shell prompt screen. Type this command to clear all visible data from
the shell prompt screen.
14. exit = logout. Type this at a shell prompt to logout of the current user or root account.
15. history = shows history of commands. Type this at a shell prompt to see a numbered
list of the previous 1000 commands you typed. To display a shorter list of previously
used commands, type history followed by a space and a number. For example, history
20.
16. reset = refreshes the shell prompt screen. Type this at a shell prompt to refresh the
screen if characters are unclear or appear corrupt.
17. head = showing first 10 lines
18. tail= showing last 10 lines
19. E s c + = copy the last argument of the previous command
20. C t r l + k= Clear from the cursor to the end
21. C t r l + L e f t A r row= Jump to the beginning ofthe previous word](https://image.slidesharecdn.com/shihab2-180314190508/85/RedHat-CentOs-Commands-for-administrative-works-1-320.jpg)
![IDB-BISEW
MD. SHIHAB HOSSAIN
Starting terminal
Application utilities terminal
Empty desktop right click terminal
Changing hostname
Hostnamectl set-hostname ‘’desired name’’
Command Basic
Command Option argument
Usermod -l shihab
Set local language
[root@host ~]# localctl set-locale LANG=fr_FR.utf8
yum langavailable
yum langinstall code
BashShell
[student@despktopX ~]# Super user interface
[student@despktopX ~]$ Regular user interface](https://image.slidesharecdn.com/shihab2-180314190508/85/RedHat-CentOs-Commands-for-administrative-works-2-320.jpg)
RedHat/CentOs Commands for administrative works
- 1. IDB-BISEW MD. SHIHAB HOSSAIN A simple keyboard shortcuts layout 1. [Ctrl] + [Alt] + [Backspace] = kills your current X session. 2. [Ctrl] + [Alt] + [Delete] = From a non-graphical shell prompt, shuts down your Red Hat Enterprise Linux system. 3. [Ctrl] + [Alt] + [Fn] = switches screens. [Ctrl]+[Alt] + one of the function keys displays an available screen. By default, [F1] through [F6] are text-mode shell prompt screens and [F7] is the graphical desktop screen. 4. [Alt] + [Tab] = switches tasks in a graphical desktop environment. 5. [Ctrl] + [a] = moves cursor to the beginning of a line. 6. [Ctrl] + [d] = logout of (and close) shell prompt. [Ctrl] + [e] = moves cursor to end of a line. This works in most text editors and in the URL field in Mozilla. 7. [Ctrl] + [l] = clears the terminal 8. 9. [Ctrl] + [u] = clears the current line. a. . 10. [Middle Mouse Button] = pastes highlighted text. 11. [Tab] = command autocomplete 12. [Up] and [Down] Arrow = shows command history. 13. clear = clears the shell prompt screen. Type this command to clear all visible data from the shell prompt screen. 14. exit = logout. Type this at a shell prompt to logout of the current user or root account. 15. history = shows history of commands. Type this at a shell prompt to see a numbered list of the previous 1000 commands you typed. To display a shorter list of previously used commands, type history followed by a space and a number. For example, history 20. 16. reset = refreshes the shell prompt screen. Type this at a shell prompt to refresh the screen if characters are unclear or appear corrupt. 17. head = showing first 10 lines 18. tail= showing last 10 lines 19. E s c + = copy the last argument of the previous command 20. C t r l + k= Clear from the cursor to the end 21. C t r l + L e f t A r row= Jump to the beginning ofthe previous word
- 2. IDB-BISEW MD. SHIHAB HOSSAIN Starting terminal Application utilities terminal Empty desktop right click terminal Changing hostname Hostnamectl set-hostname ‘’desired name’’ Command Basic Command Option argument Usermod -l shihab Set local language [root@host ~]# localctl set-locale LANG=fr_FR.utf8 yum langavailable yum langinstall code BashShell [student@despktopX ~]# Super user interface [student@despktopX ~]$ Regular user interface
- 3. IDB-BISEW MD. SHIHAB HOSSAIN Changing Password and status passwd location: file / e t c / passwd word count wc = for counting word Example: wc /etc/passwd History = for getting command history Time and date Example: timedatectl set-time 22:31:14 timedatectl set-timezone America/New_York Manpage= for Manual Man –k= for specific keyword PWD= for getting information of present working directory cd= for changing directory cd..= for parent directory directly
- 4. IDB-BISEW MD. SHIHAB HOSSAIN touch= for creating file instantly ll= for listing desired information ls –al= for listing the current location with hidden file cp= for copy mv= for move/rename rm= for remove mkdir=making directory cp –r= copy directory rm –r = removing directory grep= for specific topic query(Ex: grep “model name” /proc/cpuinfo will give cpuinfo instantly)
- 5. IDB-BISEW MD. SHIHAB HOSSAIN vim= for editing text ( I for insert, v for visualmode, esc for initial mode, wq/x for saveand quit) gedit= For graphicaltext editing nano= used also for editing text pinfo= To view the file information tar = for archiving files and folder (-c for create, -x for extract), rm –rf ‘’foldername’’ for deleting zipped id= for getting user id ps= for process information uid= for getting uid number su= for switching user useradd= to add user usermod= to modify user account (Ex: usermod -l shihab for lock user) –u for unlock groupadd= to add group groupmod= to modify group (-n for new name, -g for GID) groupdel= for deleting group Password aging Chage(-d for minimum days forcing password login,-lfor listing the currentuser settings, -E for expired days) Sudo= for delegating user with specific access) File permission r= read w= write x= execute drwxr= directory read write and execute permission has been assigned chmod=changing permission( u,g,o,a for ‘who’ +/- remarks add/remove permission, rwx for ‘which’)
- 6. IDB-BISEW MD. SHIHAB HOSSAIN chown= to change the userownership (ex: chown - R student foodir) umask= for masking or unmasking the user permission by using value.( 0 for will not musk, 007 for other permission) kill= forkillingprocess.(ex: kill pidforkillingspecificprocessid) killall=forkillingall processwithPID uptime= for systemuptime information top= runninggraphical interface systemd= systemstartupand serverprocessmanger systemctl=Query the state of all units to verify a system startup.(Ex: systemctl --type=service) (Ex: systemctl is - active sshd will show particular active unit - all will show all active and inactive) Daemon We should add ‘’d’’ after any service for daemon EX: sudo systemctl is - enabled sshd Mask/unmask= Masking will create a link in the configuration directories so that if the service is started nothing will happen. EX: systemctl mask network systemctl unmask network ssh= for establishing remote connection (EX: ssh 192.168.10.10 ssh remoteuser@)remotehost hostname) systemctl restart sshd= for restarting only ssh service ssh-keygen= for creating ssh service private key
- 7. IDB-BISEW MD. SHIHAB HOSSAIN IP addresses Ip addr show eth0= For getting assigned ip address on the Ethernet ping netstat ip route traceroute ‘’nmcli’’ for networking nmcli con show= showing connection status nmcli con show –active= showing active connection nmcli dev status= for getting device status nmcli dev show eth0 = specific device status nmcli con add con - name " default " type ethernet ifname eth0= add a connection profile nmcli con add con - name " static " ifname eth0 autoconnect no type= assigning ip address ethernet ip4 172.25.X.10/24 gw4 172.25.X.254 nmcli con up eth0= turning on the connection profile nmcli con reload= for reloading present connection getent getent hosts hostname= for testing host name resolution yum For updating, installing software and related repository packages