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Common Commands (CentOS 7)

Common commands for CentOS 7 specific Operating Systems are below

 

Basic Configuration

 



Query or System Locale


localectl

 



Display the Current Time and Date


date
timedatectl

 



Sync Date and Time


timedatectl

 



Configure SSH


/etc/ssh/ssh_config
/etc/ssh/sshd_config

 

Jobs and Services

 



List all Services


systemctl -at service
ls /etc/systemd/system/*.service
ls /usr/lib/systemd/system/*.service

 



List Services that are Running


systemctl -t service –state=active

 



Start and Stop services. Replace <service> with the name of the service


systemctl start <service>
systemctl stop <service>

 



Enable and Disable Services. Replace <service> with the name of the service


systemctl enable <service>
systemctl disable <service>

 



Check Service Status. Replace <service> with the service name


systemctl status <service>

 



See if a Service is Enabled. Replace <service> with the service name


systemctl is-enabled <service>

 



Configure Logs


/etc/rsyslog.conf
/etc/rsyslog.d/*.conf

 



View Logs


/var/log
journalctl

 



Find Files


find

 



Create Archive


tar
cpio

 

Kernel, Boot, Hardware

 



Single user Rescue Mode


append rd.break or init=/bin/bash to kernel cmdline

 



Power Off System


poweroff
systemctl poweroff

 



Halt System


halt
systemctl halt

 



Reboot System


reboot
systemctl reboot

 



Configure GRUB


/etc/default/grub
grub2-mkconfig
grub-set-default

 



View Kernel Parameters


sysctl -a
cat /proc/cmdline

 



Load Kernel Module


modprobe

 



View Kernel Version


rpm -q kernel
uname -r

 

Software Management

 



Install Software


yum install
yum group install

 



View Software Info


yum info
yum group info

 



Update Software


yum update

 



Upgrade Software


yum upgrade

 



Configure Software Repositories


/etc/yum.repos.d/*.repo

 



Find Package Owning File


rpm -qf filename
yum provides filename-glob

 



View Software Version


rpm -q packagename

 



View Installed Software


rpm -qa
yum list installed

 

User Management

 



Create User


useradd

 



Delete User


userdel

 



View or Change User Details


usermod
/etc/passwd
vipw
id

 



Create User Group


groupadd

 



Delete User Group


groupdel

 



Change Group Details


groupmod
/etc/group

 



Change User Password


passwd

 



Change User Permissions


usermod
visudo

 



Change Group Permissions


groupmod
visudo

 



Change Password Policy


chage

 



View User Sessions


w

 

File Systems, Volumes and Disks

 



Create / Modify Disk Permissions


fdisk
gdisk
parted
ssm create

 



Format Disk Partitions


mkswap

 



Defragment Disk Space


fsck

 



Mount Storage


mount
/etc/fstab

 



Mount and Activate Swap


/etc/fstab
swapon -a

 



View Free Disk Space


df

 



Check or Repair File System


fsck

 



Change File Permissions


chmod
chown
chgrp
umask

 



Change File Attributes


chattr

 



Change Access Control List


setfacl

 

Networking

 



Change Name Resolution


/etc/hosts
/etc/resolv.conf

 



Configure Hostname


hostnamectl
/etc/hostname

 



View Network Interface Information


ip addr
teamdctl
bridge

 



View Routes


ip route

 



Configure Routes


ip route add

 



Configure Firewall


firewall-cmd

 



View Ports / Sockets


ss
lsof

 

Security and Identity

 



Configure Security System


/etc/selinux/config
chcon
restorecon
semanage
setsebool

 



LDAP, SSSD


authconfig
authconfig-tui

 



Network Users


getent

 

Resource Management

 



Change Process Priority


nice
renice

 



Change Process Run Location


taskset

 



Kill a Process


kill
pkill

 



View System Usage


top
ps
ss
vmstat

 



View Disk Usage


df

 

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