Linux Cheat Sheet – AlmaLinux 8, CentOS 8, CentOS 7, CentOS 6, CentOS 5

TASK	CentOS5	CentOS6	CentOS7	CentOS8/AlmaLinux8
Graphical configuration tools	system-config-*	system-config-*	gnome-control-center	gnome-control-center
Text-based configuration tools	system-config-*-tui	system-config-*-tui
Configure printer	system-config-printer	system-config-printer	system-config-printer	gnome-control-center
Configure network	system-config-network	system-config-network	nmcli nmtui nm-connection-editor	nmcli nmtui nm-connection-editor gnome-control-center
Configure system language	system-config-language	system-config-language	localectl	localectl gnome-control-center
Configure time and date	system-config-date date	system-config-date date	timedatectl date	timedatectl date gnome-control-center
Synchronize time and date	ntpdate /etc/ntp.conf	ntpdate /etc/ntp.conf	timedatectl /etc/chrony.conf ntpdate	timedatectl date /etc/chrony.conf chronyc
Configure keyboard	system-config-keyboard	system-config-keyboard	localectl	localectl gnome-control-center
Configure SSH	/etc/ssh/ssh_config /etc/ssh/sshd_config ~/.ssh/config ssh-keygen	/etc/ssh/ssh_config /etc/ssh/sshd_config ~/.ssh/config ssh-keygen	/etc/ssh/ssh_config /etc/ssh/sshd_config ~/.ssh/config ssh-keygen	/etc/ssh/ssh_config /etc/ssh/sshd_config ~/.ssh/config ssh-keygen

TASK	CentOS5	CentOS6	CentOS7	CentOS8/AlmaLinux8
View version information	hostnamectl rpm -qa centos-release cat /etc/os-release cat/etc/centos-release	hostnamectl rpm -qa centos-release cat /etc/os-release cat/etc/centos-release	hostnamectl rpm -qa centos-release cat /etc/os-release cat/etc/centos-release	hostnamectl rpm -qa centos-release cat /etc/os-release cat/etc/centos-release
View system profile	sosreport dmidecode hwbrowser	sosreport dmidecode lstopo lscpu	sosreport dmidecode lstopo lscpu	sosreport dmidecode lstopo lscpu cat /proc/cpuinfo lshw

TASK	CentOS5	CentOS6	CentOS7	CentOS8/AlmaLinux8
Single user/rescue mode	append 1 or s or init=/bin/bash to kernel cmdline	append 1 or s or init=/bin/bash to kernel cmdline	append 1 or s or rd.break or init=/bin/bash to kernel cmdline	append 1 or s or rd.break or init=/bin/bash to kernel cmdline
Shut down system	shutdown	shutdown	shutdown	shutdown
Power off system	poweroff	poweroff	poweroff systemctl poweroff	poweroff systemctl poweroff
Halt system	halt	halt	halt systemctl halt	halt systemctl halt
Reboot system	reboot	reboot	reboot systemctl reboot	reboot systemctl reboot
Configure default run level/target	/etc/inittab	/etc/inittab	systemctl set-default	systemctl set-default
Configure GRUB bootloader	/boot/grub/grub.conf	/boot/grub/grub.conf	/etc/default/grub grub2-mkconfig grub-set-default	/etc/default/grub grub2-mkconfig grub-set-default
Configure kernel module	modprobe	modprobe	modprobe	modprobe
View hardware configured	hwbrowser	lshw	lshw	lshw
Configure hardware device	udev	udev	udev	udev
View kernel parameters	sysctl -a cat /proc/cmdline	sysctl -a cat /proc/cmdline	sysctl -a cat /proc/cmdline	sysctl -a cat /proc/cmdline
Load kernel module	modprobe	modprobe	modprobe	modprobe
View kernel version	rpm -q kernel uname -r	rpm -q kernel uname -r	rpm -q kernel uname -r	rpm -q kernel uname -r
Remove kernel module	modprobe -r	modprobe -r	modprobe -r	modprobe -r

TASK	CentOS5	CentOS6	CentOS7	CentOS8/AlmaLinux8
View software info	yum info yum groupinfo	yum info yum groupinfo	yum info yum group info	yum info yum group info
Install software	yum install yum groupinstall	yum install yum groupinstall	yum install yum group install	yum install yum group install
Upgrade software	yum upgrade	yum upgrade	yum upgrade	yum upgrade
Update software	yum update	yum update	yum update	yum update
Find package owning file	rpm -qf  file-name yum provides file-name	rpm -qf  file-name yum provides file-name	rpm -qf  file-name yum provides file-name	rpm -qf  file-name yum provides file-name
Configure software repository	subscription-manager repos /etc/yum.repos.d/*.repo	subscription-manager repos /etc/yum.repos.d/*.repo	subscription-manager repos /etc/yum.repos.d/*.repo	subscription-manager repos /etc/yum.repos.d/*.repo
View software version	rpm -q package-name	rpm -q package-name	yum list installed package-name rpm -q package-name	yum list installed package-name rpm -q package-name
View installed software	rpm -qa yum list installed	rpm -qa yum list installed	rpm -qa yum list installed	rpm -qa yum list installed
Install a module			yum module install module-name	yum module install module-name
View info on a module			yum module info module-name	yum module info module-name
List available modules			yum module list	yum module list

TASK	CentOS5	CentOS6	CentOS7	CentOS8/AlmaLinux8
List running services	service --status-all	service --status-all	systemctl -t service --state=active	systemctl -t service --state=active
List all services	chkconfig --list ls /etc/init.d/	chkconfig --list ls /etc/init.d/	systemctl -at service ls /etc/systemd/system/*.service ls /usr/lib/systemd/system/*.service	systemctl list-units -at service find /etc/systemd/ /usr/lib/systemd/ /run/systemd/ -name *.service"
Enable or disable service	chkconfig service-name on chkconfig name off	chkconfig service-name on chkconfig name off	systemctl enable name.service systemctl disable name.service	systemctl enable name.service systemctl disable name.service
Start or stop service	service service-name start service service-name stop	chkconfig service-name on chkconfig service-name off	systemctl enable name.service systemctl disable name.service	systemctl enable name.service systemctl disable name.service
Check if the service is enabled	chkconfig name --list	chkconfig name --list	systemctl is-enabled name	systemctl is-enabled name
View service status	service name status	service name status	systemctl status name.service	systemctl status name.service
Modify configuration or Create new service file	chkconfig --add	chkconfig --add	systemctl daemon-reload /etc/systemd/system/*.service	systemctl daemon-reload /etc/systemd/system/*.service
View run level/target	runlevel who -r	runlevel who -r	systemctl get-default who -r	systemctl get-default who -r
Change run level/target	/etc/inittab init run_level	/etc/inittab init run_level	systemctl isolate name.target systemctl set-default	systemctl isolate name.target systemctl set-default
Configure logging	/etc/syslog.conf	/etc/rsyslog.conf	/etc/rsyslog.conf /etc/rsyslog.d/*.conf /var/log/journal systemd-journald.service	/etc/rsyslog.conf /etc/rsyslog.d/*.conf /var/log/journal systemd-journald.service
Configure system audit	add  audit=1 to kernel cmdline auditctl /etc/audit/auditd.conf /etc/audit/audit.rules authconfig /etc/pam.d/system-auth pam_tty_audit kernel module	add  audit=1 to kernel cmdline auditctl /etc/audit/auditd.conf /etc/audit/audit.rules authconfig /etc/pam.d/system-auth pam_tty_audit kernel module	add  audit=1 to kernel cmdline auditctl /etc/audit/auditd.conf /etc/audit/audit.rules authconfig /etc/pam.d/system-auth pam_tty_audit kernel module	add audit=1 to kernel cmdline auditctl /etc/audit/auditd.conf /etc/audit/audit.rules authconfig /etc/pam.d/system-auth tlog
View audit output	aureport /var/log/faillog	aureport /var/log/faillog	/var/log journalctl
Schedule tasks	cron at batch	cron at batch	cron at batch	cron at batch systemd-run --on-calendar
Find file by name	locate	locate	locate	locate
Find file by property	find	find	find	find
Create archive	tar cpio zip xz	tar cpio zip xz	tar cpio zip xz	tar cpio zip xz
View logs	/var/log	/var/log	/var/log journalctl	/var/log journalctl

TASK	CentOS5	CentOS6	CentOS7	CentOS8/AlmaLinux8
Create user account	useradd	useradd	useradd	useradd
Graphical user management	system-config-users	system-config-users	system-config-users	system-config-users gnome-control-center
Delete user account	userdel	userdel	userdel	userdel
View or change user account details	usermod /etc/passwd vipw id	usermod /etc/passwd vipw id	usermod /etc/passwd vipw id	usermod /etc/passwd vipw id
Create user group	groupadd	groupadd	groupadd	groupadd
Change group details	groupmod /etc/group	groupmod /etc/group	groupmod /etc/group	groupmod /etc/group
Delete user group	groupdel	groupdel	groupdel	groupdel
Change user password	passwd	passwd	passwd	passwd
Change user permissions	usermod visudo	usermod visudo	usermod visudo	usermod visudo
Change group permissions	visudo groupmod	visudo groupmod	visudo groupmod	visudo groupmod
Change password policy	chage	chage	chage	chage
View user sessions	w	w	w	w

TASK	CentOS5	CentOS6	CentOS7	CentOS8/AlmaLinux8
Default file system	ext3	ext4	xfs	xfs
Format disk partition	mkfs.filesystem_type (ext3) mkswap	mkfs.filesystem_type (ext3) mkswap	mkfs.filesystem type (ext3) mkswap ssm create	mkfs.filesystem type (ext3) mkswap ssm create
Create or modify disk partitions	parted fdisk	parted fdisk	fdisk gdiskparted ssm create	parted fdisk gdisk ssm_create
Mount storage	mount /etc/fstab	mount /etc/fstab	mount /etc/fstab ssm mount	mount /etc/fstab ssm mount
Mount and activate swap	/etc/fstab swapon -a	/etc/fstab swapon -a	/etc/fstab swapon -a	/etc/fstab swapon -a
Configure static mounts	/etc/fstab	/etc/fstab	/etc/fstab	/etc/fstab
View logical volume	lvdisplay lvs vgdisplay vgs pvdisplay pvs	lvdisplay lvs vgdisplay vgs pvdisplay pvs	lvdisplay lvs vgdisplay vgs pvdisplay pvs	lvdisplay lvs vgdisplay vgs pvdisplay pvs
Create physical volume	pvcreate	pvcreate	pvcreate ssm create	pvcreate ssm create
Create volume group	vgcreate	vgcreate	vgcreate ssm create	vgcreate ssm create
Create logical volume	lvcreate	lvcreate	lvcreate ssm create	lvcreate ssm create
Extend volume	vgextend lvextend resize2fs	vgextend lvextend resize2fs	vgextend lvextend xfs_growfs ssm resize	vgextend lvextend xfs_growfs ssm resize
Shrink volumes	resize2fs lvreduce vgreduce	resize2fs lvreduce vgreduce
Repair file system	fsck	fsck	fsck ssm check	fsck ssm check
View NFS share	showmount -e mount	showmount -e mount	showmount -e mount	showmount -e mount
Configure NFS share	/etc/exports service nfs reload	/etc/exports service nfs reload	/etc/exports systemctl reload nfs.service	/etc/exports systemctl reload nfs.service
Change file attributes	chattr	chattr	chattr	chattr
Change file permissions	chmod chown chgrp umask	chmod chown chgrp umask	chmod chown chgrp umask	chmod chown chgrp umask
Change access control list	setfacl	setfacl	setfacl	setfacl

TASK	CentOS5	CentOS6	CentOS7	CentOS8/AlmaLinux8
Configure name resolution	/etc/hosts /etc/resolv.conf	/etc/hosts /etc/resolv.conf	/etc/hosts /etc/resolv.conf nmcli con mod	/etc/hosts /etc/resolv.conf nmcli con mod
Configure hostname	/etc/sysconfig/network	/etc/sysconfig/network	hostnamectl /etc/hostname nmtui	hostnamectl /etc/hostname nmtui
Network interface details	ip addr ifconfig brctl	ip addr ifconfig brctl	ip add nmcli dev show teamdctl brctl bridge	ip add nmcli dev show teamdctl brctl bridge
View routes	ip route	ip route	ip route	ip route
Configure routes	ip route add system-config-network /etc/sysconfig/route-iface	ip route add system-config-network /etc/sysconfig/route-iface	ip route add nmcli nmtui nm-connection-editor /etc/sysconfig/route-iface	ip route add nmcli nmtui nm-connection-editor /etc/sysconfig/route-iface

TASK	CentOS5	CentOS6	CentOS7	CentOS8/AlmaLinux8
Server security	/etc/selinux/config chcon restorecon semanage setsebool system-config-selinux	/etc/selinux/config chcon restorecon semanage setsebool system-config-selinux	/etc/selinux/config chcon restorecon semanage setsebool system-config-selinux	/etc/selinux/config chcon restorecon semanage setsebool system-config-selinux
LDAP, SSSD, Kerberos	authconfig authconfig-tui authconfig-gtk	authconfig authconfig-tui authconfig-gtk	authselect	authselect
Network users	getent	getent	getent	getent

TASK	CentOS5	CentOS6	CentOS7
Trace library calls	ltrace	ltrace	ltrace
Trace system calls	strace	strace	strace
Change process run location	taskset	taskset	taskset
Change process priority	nice renice	nice renice	nice renice
Kill process	kill pkill killall	kill pkill killall	kill pkill killall
View system usage	top ps sar iostat netstat vmstat mpstat numastat	top ps sar iostat netstat ss vmstat mpstat numastat tuna	top ps sar iostat netstat ss vmstat mpstat numastat tuna