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systemctl list-unit-files -at service
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Lists enabled/disabled service unit files.
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systemctl list-units -at service
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Lists enabled/disabled running services.
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systemctl list-units -t service --state running
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Shows active running services.
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-t
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Shows enabled service unit files.
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-a
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Shows both enabled and disabled service unit files.
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systemctl mask [service name]
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Prevents service from starting.
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/var/spool/cron/[user]
|
User cron jobs.
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/etc/cron.d
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System cron jobs.
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[minute 0-59] [hour] [day of the month] [month of the year] [day of the week] [path of script]
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Cron job time format.
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crontab-generator.org
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Crontab generator.
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0 1 *
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Runs job everyday at 1 a.m.
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0 1 * [user]
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Format for system wide cron jobs.
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/etc/at.allow
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Allow access to the AT services.
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/etc/cron.allow
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Allow access to cron services.
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/etc/at.deny
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/etc/cron.deny
|
|
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rpm -qa
|
Queries all installed packages.
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rpm -qa | sort
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|
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rpm -qi [package]
|
Shows information about the package.
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rpm -qa Group="System Environment/Shells"
|
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rpm --qa -last
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Shows packages install sorted by date
|
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rpm -ql yum
|
Queries for list of file paths.
|
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rpm -qc yum
|
|
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rpm -qf [path to file]
|
Query file.
|
|
rpm -qdf [path to file]
|
Shows all documentation for specified command/file.
|
|
rpm -q --provide
|
|
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rpm -q --requires [file]
|
|
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rpm -q --changelog [file]
|
Shows changes to package.
|
|
Enforcing mode
|
Security policy is enforced.
|
|
Permissive mode
|
Security policy is observed and warnings are printed but policy is not enforced.
|
|
Disabled
|
Mandatory access control if turned off.
|
|
sestatus
|
Shows SELinux status.
|
|
set setenforce <mode>
|
Temporarily changes SELinux mode.
|
|
vi /selinux/config
|
SELinux config file.
|
|
nmtui
|
graphical network editor
|
|
less -N /etc/rsyslog.conf
|
View rsyslog configuration file with line numbering turned on.
|
|
cat /var/log/messages
|
Lists messages log.
|
|
grep -v 'systemd:' /var/log/messages
|
Lists everything that does not include systemd.
|
|
tail -f /var/log/messages
|
Follows log file.
|
|
/var/log/secure
|
Private authentication messages (logins)
|
|
/etc/cron.daily
|
Logrotate cron job.
|
|
/etc/logrotate.conf
|
Logrotate configuration file.
|
|
logger "message"
|
Writes message to messages log file.
|
|
yum --showduplicates -list [pacakge name]
|
Shows versions of a package.
|
|
yum list installed
|
Lists all packages installed.
|
|
Bold
|
Update available in repository.
|
|
Bold and underline
|
Current kernel
|
|
Red
|
Package doesn't exist in repository.
|
|
Yellow
|
Newer package then in repository.
|
|
yum list updates
|
Lists updates for packages installed.
|
|
yum list available
|
|
|
yum info [package name]
|
Shows package info.
|
|
yum deplist [package name]
|
Shows dependencies for package.
|
|
yum search [package name]
|
Searches for package name.
|
|
yum reinstall [package name]
|
Reinstalled package.
|
|
yum reinstall --skip-broken [package name]
|
|
|
yum remove [package name]
|
Removes package.
|
|
yum autoremove [package name]
|
Removes packages including dependencies.
|
|
yum package-cleanup
|
Shows unused packages.
|
|
yum install yum-utils
|
|
|
yum check-update
|
Checks for updates.
|
|
yum list obsoletes
|
|
|
yum install yum-plugin-versionlock
|
|
|
yum versionlock [package name]
|
Prevents package from updating.
|
|
yum versionlock
|
Lists version locked packages.
|
|
yum versionlock delete [output from yum versionlock]
|
Removes version lock from package.
|
|
yum update --security
|
Only updates security packages.
|
|
yum update-minimal --security
|
Install strictly security updates. Doesn't include bug fixes.
|
|
yum install yum-plugin changelog
|
View package change logs.
|
|
yum changelog updates
|
Gets all change logs for packages with updates.
|
|
yum changelog [package name]
|
View change log for specific package.
|
|
yum list installed kernel-*
|
Lists currently installed kernel.
|
|
ls -l /boot
|
Kernel directory.
|
|
uname -r
|
Shows running kernel.
|
|
yum list available kernel
|
Lists available kernel.
|
|
yum -y update kernel
|
Updates kernel.
|
|
yum remove kernel
|
|
|
grub2-set-default [kernel number]
|
Changes kernel.
|
|
ls /lib/modules/$(uname -r)/kernel
|
Lists kernel module directory.
|
|
lsmod
|
Lists modules.
|
|
timedatectl
|
Lists local time for current timezone.
|
|
timedatectl list-timezones | grep America
|
Filters timezones via grep.
|
|
timedatectl set-timezone [timezone]
|
Sets timezone.
|
|
timedatectl set-time 24:00:00
|
Manually sets time.
|
|
timedatectl set-time 2018-12-30
|
Manually sets date.
|
|
timedatectl set-ntp true
|
Enables NTP.
|
|
systemctl restart systemd-timedated
|
Restarts NTP service.
|
|
yum install ntp
|
Installs NTP client.
|
|
/etc/ntp.conf
|
NTP config file.
|
|
ntpdate -q <server address>
|
Checks NTP server address.
|
|
ntpdate <server address>
|
Sets NTP server.
|
|
systemctl enable ntpdate
|
Enables NTP synchronization.
|
|
journalctl
|
Lists all journal entries.
|
|
journalctl /sbin/crond
|
Specifies journal.
|
|
journalctl -f
|
Tails journal.
|
|
mkdir /var/log/journal
|
Directory for persistent journals.
|
|
ls -l [file name]
|
Lists group owners.
|
The user-owner is the third column from the left. THe group-owner is the fourth column.
|
|
Read (r)
|
4
|
|
|
Write (w)
|
2
|
|
|
Execute (x)
|
1
|
|
|
-rw-rw-r--
|
--userowner-groupowner-other
|
|
|
chmod u=rwx,g=rx,o= <file>
|
Symbolic permission format.
|
|
|
chmod u+rwx <file>
|
Adds permissions format.
|
|
|
chmod o-x <file>
|
Remove permissions format.
|
|
|
chmod a-x <file>
|
Removes execute from all positions.
|
|
|
-R
|
Recursively adds permissions.
|
|
|
umask
|
View umask.
|
|
|
umask -S
|
View umask in symbolic notation.
|
|
|
775
|
Default directory permissions.
|
rwxrwxrwx
|
|
755
|
rwx-r-xr-x
|
|
|
664
|
Default file permissions. (umask 002)
|
rw-rw-r--
|
|
umask 022
|
Changes umask.
|
|
|
umask 002
|
rw-rw-r--
|
Directories- rwx-r-xr-x, Files- rwxr--r--
|
|
vi ~/bashrc
|
User umask startup file
|
add new umask to end of file.
|
|
vi /etc/profile.d/unmash.sh
|
System wide unmask.
|
if [ "$UID" -ge 1000] ;then
|
|
getfacl <file>
|
lists ACLs on file.
|
-t
|
|
setfacl -m user:<user>:<permissions> aclfile
|
Sets ACLs on file.
|
setfacl -m user:root:rwx /home/file.txt
|
|
setfacl -m group:<group>:<permission> <file>
|
||
|
setfacl -x group:root <file/dir>
|
-x remove specific ACL, -k removes all default ACLs, -b removes all ACLs
|
|
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