To see all Open files
lsof
To see all network activity
lsof -i
See the connections on port 80
lsof -i :80
To see all files opened by a process
lsof -p PID
To see all files opened by a process and refresh it every 5 seconds, run
lsof -p PID_HERE -r 5
See Linux Commands
First you need to install Remi repository
Enable epel repo with
yum install epel-release -y
On CentOS 7
rpm -ivh https://rpms.remirepo.net/enterprise/remi-release-7.rpm
On CentOS 6
rpm -ivh https://rpms.remirepo.net/enterprise/remi-release-6.rpm
Enable PHP 7.2
yum install yum-utils yum-config-manager --enable remi-php72
To install PHP, run
yum install -y php php-bcmath php-cli php-common php-devel php-gd \
php-imap php-intl php-json php-ldap php-lz4 php-mbstring php-mysqlnd \
php-soap php-intl php-opcache php-xml php-pdo
Downgrading PHP version
if you ever want to change PHP version, lets say PHP 7.0, do the following. Remove current PHP
rpm -qa | grep php | xargs yum remove -y
Disable PHP 7.2 repo.
yum-config-manager --disable remi-php72
Enable PHP 7.0 repo
yum-config-manager --enable remi-php70
Now install PHP as above.
PHp Binary
PHP cli will be installed in /usr/bin/php72, you can create a symlink if you want.
PHP-FPM
To install php-fpm module, run
yum install php72-php-fpm -y
To start php-fpm, run
systemctl start php72-php-fpm
To install haproxy on Ubuntu, run
apt install haproxyHaproxy config file is located at
/etc/haproxy/haproxy.cfgEnable HTTP_X_FORWARDED_FOR in Haproxy
Show X-Forwarded-For IP in Apache
Haproxy Site With SSL
Enable SSL in Haproxy Docker Container
Good Plugins
Some of the special URLs/settings pages
chrome://settings/content chrome://plugins chrome://net-internals/#events chrome://net-internals/#dns
To install Google Chrome on CentOS 7 (Chrome won’t work on CentOS 6 as it is using older version of libraries required for Chrome).
First create repo file
vi /etc/yum.repos.d/google-chrome.repo
Add following content
[google-chrome] name=google-chrome baseurl=http://dl.google.com/linux/chrome/rpm/stable/x86_64 enabled=1 gpgcheck=1 gpgkey=https://dl-ssl.google.com/linux/linux_signing_key.pub
Now you can install google chrome with command
yum -y install google-chrome-stable
See CentOS
screen allows you to run commands in the remote server even after you disconnect.
disconnect from a session
Press
CTRL + A, then press CTRIL +D in quick succession.
You can also close the terminal, the screen session will continue in the background.
| screen -ls | List all available screen sessions |
| screen -r | Reconnect to a disconnected screen session |
On Ubuntu
Default config look like
root@zecurecode:~# cat /etc/network/interfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # Source interfaces # Please check /etc/network/interfaces.d before changing this file # as interfaces may have been defined in /etc/network/interfaces.d # See LP: #1262951 source /etc/network/interfaces.d/*.cfg root@zecurecode:~#
/etc/network/interfaces.d/50-cloud-init.cfg is used to auto configure network interface with dhcp.
root@zecurecode:~# cat /etc/network/interfaces.d/50-cloud-init.cfg
# This file is generated from information provided by
# the datasource. Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
auto lo
iface lo inet loopback
auto ens3
iface ens3 inet dhcp
root@zecurecode:~#
First find the gateway used by the VPS.
root@zecurecode:~# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 51.254.32.1 0.0.0.0 UG 0 0 0 ens3 51.254.32.1 0.0.0.0 255.255.255.255 UH 0 0 0 ens3 root@zecurecode:~#
We found the gateway IP 51.254.32.1
The VPS had main IP of the server is 51.254.35.58 and secondary IPS 94.23.153.137, 178.32.52.159, 178.32.49.157
Here is the modified /etc/network/interfaces
root@zecurecode:~# cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# Source interfaces
# Please check /etc/network/interfaces.d before changing this file
# as interfaces may have been defined in /etc/network/interfaces.d
# See LP: #1262951
#source /etc/network/interfaces.d/*.cfg
auto ens3
iface ens3 inet static
address 51.254.35.58
netmask 255.255.255.255
broadcast 51.254.35.58
post-up route add 51.254.32.1 dev ens3
post-up route add default gw 51.254.32.1
post-down route del default gw 51.254.32.1
post-down route del 51.254.32.1 dev ens3
auto ens3:1
iface ens3:1 inet static
address 94.23.153.137
netmask 255.255.255.255
broadcast 94.23.153.137
auto ens3:2
iface ens3:2 inet static
address 178.32.52.159
netmask 255.255.255.255
broadcast 178.32.52.159
auto ens3:3
iface ens3:3 inet static
address 178.32.49.157
netmask 255.255.255.255
broadcast 178.32.49.157
root@zecurecode:~#
Here is a PHP script to create OVH failover IP config for Ubuntu/Debian.
https://gist.github.com/serverok/991f7ccd1be36cbc579e8d55caf39715
To generate SSH key, run
ssh-keygen -t ed25519If you need RSA key, run
ssh-keygen -b 4096To create an SSH key in the current folder, run
ssh-keygen -b 4096 -N "" -f NAME_OF_KEYThis will create 2 files in the current directory. The “-N” option is for keyphrase. With -N “”, it won’t ask you for kayphrase.
To change SSH key passphrase, run
ssh-keygen -p -f ~/.ssh/id_rsa
Example
root@ok:~/.ssh# ssh-keygen -p -f ~/.ssh/id_rsa Enter new passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved with the new passphrase. root@ok:~/.ssh#
See ssh-keygen
lsblk list all block level devices available on your system.
Example
root@ok:~# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 100G 0 disk ├─sda1 8:1 0 98G 0 part / ├─sda2 8:2 0 1K 0 part └─sda5 8:5 0 2G 0 part [SWAP] sdb 8:16 0 700G 0 disk └─sdb1 8:17 0 700G 0 part /backup sr0 11:0 1 655M 0 rom loop0 7:0 0 36.4M 1 loop /snap/heroku/1513 loop1 7:1 0 83.8M 1 loop /snap/core/3748 loop2 7:2 0 16M 1 loop /snap/heroku/1527 root@ok:~#
See fs
After installing r1soft backup agent, you need to add the server to R1Soft Server Backup Manager SE.
Click on “Protected Machines” link on left side menu.
Click on “New Machine” button.
On this page, enter following details “Machine Name” and “Hostname / IP”. I used host name as Machine Name. Then used IP address. I don’t enable Encryption, you can enable it for added security.
Click Save button.
Now login to server where Backup Agent is installed (Protected Machine) and run
serverbackup-setup --get-key http://url-of-backup-manager-server
Example
[root@server1 ~]# serverbackup-setup --get-key https://22536.r1softlicenses.com Key '22536.r1softlicenses.com' successfully installed [root@server1 ~]#
Now verify key is added with command
[root@server1 ~]# serverbackup-setup --list-keys
Installed keys:
22536.r1softlicenses.com
1 keys installed
[root@server1 ~]#
Next, you need to Configure Server Backup in R1Soft Backup Manager