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distros:centos

Information

  • CentOS 7

Download

Software

Update

sudo yum clean 'all' && sudo yum update -y && sync

General

sudo yum install htop p7zip unar aria2 hdparm nano unzip

Settings

Nano as default editor

sudo nano '/etc/sudoers.d/nano'
Defaults editor = /usr/bin/nano

Secure Shell

Change Listen Port

  • Connect with ssh 'user@IP' -p 'x'
sudo -e '/etc/ssh/sshd_config'
Port x

Firewall

New Port

sudo firewall-cmd --permanent --add-port='x/tcp' && sudo firewall-cmd --reload
Remove Old

sudo firewall-cmd --permanent --remove-service='ssh' && sudo systemctl reboot

Kernel Settings

Security

sudo -e '/etc/sysctl.d/harden.conf'
kernel.dmesg_restrict = 1
kernel.kptr_restrict = 1

GRUB

Timeout

sudo -e '/etc/default/grub'
GRUB_TIMEOUT=3

BIOS Update

sudo grub2-mkconfig -o '/boot/grub2/grub.cfg'

Automatic Updates

Service

sudo -e '/etc/systemd/system/centos-up.service'
[Service]
Type=oneshot
ExecStart='/usr/bin/yum' clean 'all'
ExecStart='/usr/bin/yum' update -y
ExecStart='/usr/bin/sync'
ExecStart='/usr/bin/systemctl' reboot

Timer

sudo -e '/etc/systemd/system/centos-up.timer' && sudo systemctl daemon-reload && sudo systemctl enable 'centos-up.timer' --now && sudo systemctl start 'centos-up' && sudo systemctl status 'centos-up' -l
[Unit]
Description=Software Package Maintenance and Updater
Wants=network-online.target

[Timer]
OnCalendar=*-*-* 06:00:00
Persistent=true

[Install]
WantedBy=timers.target

Steven Black's Unified Hosts File

Service

sudo -e '/etc/systemd/system/hosts-up.service'
[Service]
Type=oneshot
ExecStart='/usr/bin/wget' 'https://github.com/StevenBlack/hosts/archive/master.zip' -O '/tmp/master.zip'
ExecStart='/usr/bin/unzip' '/tmp/master.zip' -d '/tmp'
ExecStart='/usr/bin/python' '/tmp/hosts-master/updateHostsFile.py' --auto --replace
ExecStart='/usr/bin/rm' -R '/tmp/master.zip' '/tmp/hosts-master'
ExecStart='/usr/bin/sync'

Timer

sudo -e '/etc/systemd/system/hosts-up.timer' && sudo systemctl daemon-reload && sudo systemctl enable 'hosts-up.timer' --now && sudo systemctl start 'hosts-up' && sudo systemctl status 'hosts-up' -l
[Unit]
Description=Hosts File Protection Updater
Wants=network-online.target

[Timer]
OnCalendar=weekly
Persistent=true

[Install]
WantedBy=timers.target

Notable Folders and Commands

Show CPU Frequency

grep 'MHz' '/proc/cpuinfo'
watch -n 0.1 grep \'cpu MHz\' '/proc/cpuinfo'

Partition Information

df -hT

Optimal GCC compiler flags

gcc -v -E -x c -march=native -mtune=native - < /dev/null 2>&1 | grep cc1 | perl -pe 's/ -mno-\S+//g; s/^.* - //g;'

Remove EXIF data

exiftool -all= *.* -overwrite_original

FirewallD

List Active Rules

sudo firewall-cmd --list-all

List Available Services

sudo firewall-cmd --get-service

Reload

sudo firewall-cmd --reload

Add/Remove Service

  • Add --permanent as-needed to allow the rule to persist
sudo firewall-cmd --add-service=x
sudo firewall-cmd --remove-service=x

Add/Remove Service

  • Add --permanent as-needed to allow the rule to persist
  • Change tcp to udp as-needed
sudo firewall-cmd --add-port=x/tcp
sudo firewall-cmd --remove-port=x/tcp
distros/centos.txt · Last modified: 2016/06/24 17:03 by Sean Rhone