Med Java - linux:centos

add-repo

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Add a yum repository rpm --import "http://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF" yum-config-manager --add-repo http://download.mono-project.com/repo/centos/

auto-lets-encrypt

Anonymous (anonymous@undisclosed.example.com) — 2025-01-03T17:11:56+00:00

Automatic generate / renew Let's Encrypt certificates Install certbot. yum install python2-certbot-apache Setup the VirtualHost *:80 entry in your apache configuration for domain.com. This will generate the certificates and the file domain.com-le-ssl.conf with the VirtualHost *:443 configuration for domain.com.

check-battery-status-command-line

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Check the battery status from command line upower -i `upower -e | grep 'BAT'` native-path: BAT1 vendor: Simplo model: DELL 4DMNG2CD serial: 0C28 power supply: yes updated: Thu 23 Mar 2023 12:07:02 PM EET (119 seconds ago) has history: yes has statistics: yes battery present: yes rechargeable: yes state: discharging warning-level: none …

copy-files-from-windows-share

Anonymous (anonymous@undisclosed.example.com) — 2025-01-02T18:22:18+00:00

Copy files from a windows share on Centos / Redhat distributions Mount the windows share First we need to mount locally the windows share folder. For this we'll use the cifs-utils package. You should use the root user for the following commands, otherwise append sudo in front of them.

crontab

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Remove cronjob for a specific user crontab -u apache -e ... then remove undesired entries.

extend-xfs-partition

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Extend XFS partition df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/centos_odcent7-root 50G 3.0G 47G 6% / devtmpfs 2.6G 0 2.6G 0% /dev tmpfs 2.6G 0 2.6G 0% /dev/shm tmpfs 2.6G 12M 2.6G 1% /run tmpfs 2.6G 0 2.6G 0% /sys/fs/cgroup /dev/sda1 1014M 191M 824M 19% /boot /dev/mapper/centos_odcent7-home …

extract-multi-part-archive

Anonymous (anonymous@undisclosed.example.com) — 2025-01-02T18:22:18+00:00

Extract Multi-Part Archive For a multi-part archive we can use 7-zip to extract it. Example of multi-part archive: export.zip export.z01 export.z02 Steps to follow Install epel-release repo Skip this step if you already have it installed.

extract-tar-gz

Anonymous (anonymous@undisclosed.example.com) — 2025-01-02T18:22:18+00:00

Extract tar.gz archive tar -xvzf export.tar.gz

find-large-files

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Find large files (higher than 100 mb) find . -type f -size +100M ./13/data/log/postgresql-Tue.log Then check it's size: ls -lh ./13/data/log/postgresql-Tue.log -rw------- 1 postgres postgres 1.3G Jan 31 19:10 ./13/data/log/postgresql-Tue.log

gnome

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Start CentOS without UI systemctl set-default multi-user.target systemctl reboot Start CentOS with UI systemctl set-default graphical.target systemctl reboot Check current mode systemctl get-default Stop GNOME UI systemctl stop gdm Restart it back when needed:

install-code-server

Anonymous (anonymous@undisclosed.example.com) — 2024-02-21T21:45:56+00:00

Install Code Server on Centos 7 sudo yum install epel-release sudo yum install snapd sudo systemctl enable --now snapd.socket sudo ln -s /var/lib/snapd/snap /snap sudo snap install code-server --candidate Restart code-server: snap restart code-server

list-packages-from-repo

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

List all installed packages from a certain repo yum list installed | grep @remi-safe

log-monitoring

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Important log files to monitor - /var/log/messages (system application logs) - /var/log/secure (all authentication events) - /var/log/boot.log (boot messages during system startup) - /var/log/dmesg (info about hardware devices and drivers) - /var/log/cron (cron jobs info) - /var/log/yum.log (monitor package changes) - /var/log/maillog (mail logs) - /var/log/dovecot.log (dovecot log file) - /home/vmail/dovecot-deliver.log (dovecot mail log) - /var/log/httpd directory (various apache logs) - /var…

mount-hard-disk

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Mount hard disk See all devices ls -1 /dev/[sv]d[a-z] Mount hdd mkdir /databkp mount /dev/sdd2 /databkp Mount CD-ROM / DVD mount /dev/sr0 /media Check all mounted devices mount -v | grep "^/" | awk '{print "\nPartition identifier: " $1 "\n Mountpoint: " $3}'

run-command-as-another-user

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Run command as another user runuser -l nginx -c 'ulimit -SHa'

services

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Create service file for an application We'll use phabricator app as example. It should run after the mysql database was started. Create the file phabricator-phd.service in /usr/lib/systemd/system/ folder. [Unit] Description=Phabricator Daemons After=syslog.target After=network.target After=mariadb.service [Service] Type=forking User=apache Group=apache ExecStart=/var/www/html/phabricator/phabricator/bin/phd start ExecStop=/var/www/html/phabricator/phabricator/bin/phd stop Restart=always Res…

show-ip

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Show ip address on linux ip addr show

software-raid1-setup

Anonymous (anonymous@undisclosed.example.com) — 2025-01-02T18:22:18+00:00

Create a software RAID 1 setup with two hard disks Intro RAID 1 = mirrored pair of two hard disks If one disk fail, the raid will continue to be operational. Read performance will be increased for parallel read operations. Write performance will be likely the same (almost the same).

update-ruby

Anonymous (anonymous@undisclosed.example.com) — 2024-02-12T23:01:57+00:00

Update ruby to a higher version in Centos 7 yum --enablerepo=centos-sclo-rh -y install rh-ruby27 scl enable rh-ruby27 bash

usb-software-raid-optimizations

Anonymous (anonymous@undisclosed.example.com) — 2025-11-20T21:53:57+00:00

Optimizing Software RAID with External USB Drives Overview This guide covers comprehensive optimization techniques for software RAID (mdadm) configurations using external USB drives. USB drives present unique challenges in RAID environments due to power management, timeouts, and connection stability issues.

view-devices

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

View all existing hdd devices df -Th lsblk -f mount blkid

vmware-clone-vm

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

VMWare Workstation clone an existing centos VM * Power off the source machine * Go to VM/Manage/Clone and follow the steps * On the cloned machine, set new host: hostnamectl set-hostname server1 * Disable not needed service: systemctl stop NetworkManager

vmware-tools

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Upgrade Vmware Tools In Centos From Virtual Machine -> VM / Upgrade VMWare Tools mount /dev/cdrom /mnt/cdromcd /tmprm -rf vmware-tools-distribcp /mnt/cdrom/VMwareTools-10.1.5.5055693.tar.gz .tar zxpf VMwareTools-10.1.5.5055693.tar.gzcd vmware-tools-distrib

vmware-turn-off-caps-notifications

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

VMWare Workstation turn off caps notifications Notifications about Caps Lock on/off or Num lock on/off can be very annoying. To disable them: * Stop (or suspend) virtual machine * Find the vmx file and add the following line: mks.keyboard.setHostLEDs = "FALSE"

x-server

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

X Server Install X Server yum groupinstall "X Window System"

yum-dependencies

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

List all the dependencies of an already installed RPM package There are 2 ways to do achieve this. Example for package java-1.8.0-openjdk: rpm -q --requires java-1.8.0-openjdk OR using yum: yum deplist java-1.8.0-openjdk Remove RPM package without dependency

yum-proxy

Anonymous (anonymous@undisclosed.example.com) — 2023-07-04T16:36:30+00:00

Set Proxy For Yum In Centos vi /etc/yum.confproxy=http://proxy.address:8080 proxy_username= proxy_password=

yum-version-lock

Anonymous (anonymous@undisclosed.example.com) — 2025-07-10T11:20:34+00:00

YUM Versionlock - Essential Commands Plugin Installation # CentOS/RHEL 7-8 sudo yum install yum-plugin-versionlock # CentOS/RHEL 9 / Rocky Linux / AlmaLinux sudo dnf install python3-dnf-plugin-versionlock Basic Commands Lock Packages # Lock currently installed version sudo yum versionlock add package-name # Lock specific version sudo yum versionlock add package-name-1.2.3 # Lock with wildcard (all versions starting with...) sudo yum versionlock add 'gitlab-ee-18*' # Lock multiple pac…