Category: Linux

  • zsh

    Install zsh in Debian/Ubuntu

    apt install zsh

    Install OhMyZsh

    sh -c "$(curl -fsSL https://raw.github.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"

    See shell

  • Free DNS Hosting

    Free DNS Hosting

    Paid DNS Hosting

    • Google Cloud DNS – $0.2 per domain. Traffic will be charged at $0.40 per million queries per month.

    Free Dynamic DNS

  • Configure Server Backup in R1Soft Backup Manager

    Configure Server Backup in R1Soft Backup Manager

    After adding Server to R1Soft Server Backup Manager, you need to configure it.

    Test Connection

    Verify backup manager can connect to protected machine. If you can’t connect, you need to open TCP port 1167 on firewall.

    Click on Wheel icon > Test Agent Connection.

    If backup manager cna connect to server, you will see

    Running First Backup

    You can click

    Wheel > Backup now

    Configure MySQL backup

    Go to

    Protected Machines > Wheel icon > Edit Policy > MySQL > Add new MySQL instance

    You will be asked to enter MySQL server login details. I created a user with remote access permission with following command.

    GRANT ALL PRIVILEGES ON *.* TO 'r1soft'@'%' IDENTIFIED BY 'YOUR_PASSWORD_HERE' WITH GRANT OPTION;
GRANT PROXY ON ''@'' TO 'r1soft'@'%' WITH GRANT OPTION;

    You may need to edit MySQL configuration and make it listen to public IP to allow R1Soft backup manager can connect to your MySQL server.

    Back to r1soft

  • Installing r1soft server backup agent on Debian/Ubuntu

    To install r1soft server backup agent on Ubuntu/Debian, add repository

    echo deb http://repo.r1soft.com/apt stable main >> /etc/apt/sources.list
wget http://repo.r1soft.com/r1soft.asc
apt-key add r1soft.asc

    Install agent

    apt update
apt -y install serverbackup-enterprise-agent

    Install kernal headers

    apt install linux-headers-`uname -r`

    Install kernal modules

    serverbackup-setup --get-module

    Verify backup agent works with

    serverbackup-setup --test-connection

    Start backup agent

    /etc/init.d/cdp-agent restart

    Now you can add the server to R1Soft Backup Manager.

  • Set default PHP version in Ubuntu

    To select default PHP version in Ubuntu, run

    update-alternatives --config  php

    This will show a menu, you can select the default php version

    root@server:/usr/bin# update-alternatives --config  php
There are 2 choices for the alternative php (providing /usr/bin/php).

  Selection    Path             Priority   Status
------------------------------------------------------------
* 0            /usr/bin/php7.0   70        auto mode
  1            /usr/bin/php5.6   56        manual mode
  2            /usr/bin/php7.0   70        manual mode

Press  to keep the current choice[*], or type selection number: 1
update-alternatives: using /usr/bin/php5.6 to provide /usr/bin/php (php) in manual mode
root@server:/usr/bin#

    After setting PHP 5.6 as default PHP version, you will see

    root@server:~# php -v
PHP 5.6.40-8+0~20190531120521.15+stretch~1.gbpa77d1d (cli) 
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies
root@server:~#
  • Install Transmission torrent client on Ubuntu Server

    Install Transmission torrent client on Ubuntu Server

    To install transmission torrent client on Ubuntu, run

    apt install transmission-cli transmission-common transmission-daemon

    Before you can configure transmission-deamon, you need to stop it.

    service transmission-daemon stop

    Edit configuration file

    vi /var/lib/transmission-daemon/info/settings.json

    Once edited, start transmission-deamon with

    service transmission-daemon start

    Settings Password

    Default user and password is “transmission”.

    You can modify it by editing config file

    "rpc-password": "{62b16db87b89a91dd49a5110a7cafc06d20eb4f2wtK6kqPj",
"rpc-username": "transmission",

    Password you can use plain text. Transmission will convert it to SHA1 encrypted format on startup,

    Allow remote access

    You need to put your IP

    "rpc-whitelist": "127.0.0.1,192.168.*.*",

    Only white listed IP can access the web interface.

    Download folder

    By default download will be stored in folder

    "download-dir": "/var/lib/transmission-daemon/downloads",

    You can modify this folder as required.

    Web interface

    Transmission web client

    Web interface can be accessed using port 9091.

    http://SERVER-IP:9091

  • linux

    CentOS
    Ubuntu
    Debian
    ArchLinux
    openSUSE

    Try Linux distro with out downloading ISO

  • Try Linux distro with out downloading ISO

    Try Linux distro with out downloading ISO

    You can try various linux distributions with out downloading ISO. To try, go to web site

    https://distrotest.net

    Find the linux distribition from the list of available operating systems.

    Try Linux on Cloud

    On next page, you will get IP address and port, that you can use to connect to the system using VNC viewer. There is option for using web based VNC client, this will open the desktop on a new browser window.

  • run same command on multiple tmux panes

    If you want to run same command on multiple servers, you can use tmux synchronize-panes feature. This will be useful when you need to setup multiple servers, say install nginx/php/mysql on multiple servers.

    You can create multiple panes in tmux. SSH into each of the servers from these panes. Now run

    CTRL + B :

    Now type

    setw synchronize-panes on

    Whatever command you run on one of the pane will be executed on all panes. Be careful when you run server specific commands.

  • tmux create new window on current directory

    When you start a new window or split pane on tmux, it always start with the directory from where you run tmux command.

    I prefer it start with current working directory of active tmux window. To do this, edit file

    vi ~/.tmux.conf

    Add

    bind c new-window -c "#{pane_current_path}"
bind '"' split-window -c "#{pane_current_path}"
bind % split-window -h -c "#{pane_current_path}"

  • Auto Attach to tmux session on SSH

    To start tmux and attach to existing connection on SSH in, edit file 

    vi ~/.bashrc

    Add

    if [[ "$TMUX" == "" ]] && [[ "$SSH_CONNECTION" != "" ]] && [ "$SSH_TTY" != "" ]; then
    WHOAMI=$(whoami)
    if tmux has-session -t $WHOAMI 2>/dev/null; then
        tmux -2 attach-session -t $WHOAMI
    else
        tmux -2 new-session -s $WHOAMI
    fi
fi

    Method 2

    You can use following command when connecting to remote sevrer.

    ssh  USER@SERVER_IP -t tmux a

  • Install MongoDB 4.0 on CentOS 7

    To install MongoDB 4.0 (for other versions, see release note) on CentOS 7, create file

    vi /etc/yum.repos.d/mongodb-org-4.0.repo

    Add content

    [mongodb-org-4.0]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/4.0/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-4.0.asc

    Install MongoDB with

    yum install -y mongodb-org

    Enable MongoDB start on boot

    systemctl enable mongod

    Start Mongo DB with

    systemctl start mongod

    To see mongoDB version, run

    [root@ns3084948 ~]# mongo --version
MongoDB shell version v4.0.10
git version: c389e7f69f637f7a1ac3cc9fae843b635f20b766
OpenSSL version: OpenSSL 1.0.1e-fips 11 Feb 2013
allocator: tcmalloc
modules: none
build environment:
    distmod: rhel70
    distarch: x86_64
    target_arch: x86_64
[root@ns3084948 ~]#

    To see if mongoDB running

    [root@ns3084948 ~]# netstat -lntp | grep mongo
tcp        0      0 127.0.0.1:27017         0.0.0.0:*               LISTEN      10349/mongod        
[root@ns3084948 ~]#

    Or use 

    [root@ns3084948 ~]# systemctl status mongod
● mongod.service - MongoDB Database Server
   Loaded: loaded (/usr/lib/systemd/system/mongod.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2019-06-04 06:08:01 BST; 18min ago
     Docs: https://docs.mongodb.org/manual
  Process: 10347 ExecStart=/usr/bin/mongod $OPTIONS (code=exited, status=0/SUCCESS)
  Process: 10344 ExecStartPre=/usr/bin/chmod 0755 /var/run/mongodb (code=exited, status=0/SUCCESS)
  Process: 10341 ExecStartPre=/usr/bin/chown mongod:mongod /var/run/mongodb (code=exited, status=0/SUCCESS)
  Process: 10338 ExecStartPre=/usr/bin/mkdir -p /var/run/mongodb (code=exited, status=0/SUCCESS)
 Main PID: 10349 (mongod)
   Memory: 46.7M
   CGroup: /system.slice/mongod.service
           └─10349 /usr/bin/mongod -f /etc/mongod.conf

Jun 04 06:07:57 ns3084948.ip-145-239-4.eu systemd[1]: Starting MongoDB Database Server...
Jun 04 06:07:58 ns3084948.ip-145-239-4.eu mongod[10347]: 2019-06-04T06:07:58.013+0100 I CONTROL  [main] WARNING: Cannot detect if NUMA interleaving is enabled. Failed to probe "/sys/devices...ssion denied
Jun 04 06:07:58 ns3084948.ip-145-239-4.eu mongod[10347]: about to fork child process, waiting until server is ready for connections.
Jun 04 06:07:58 ns3084948.ip-145-239-4.eu mongod[10347]: forked process: 10349
Jun 04 06:08:01 ns3084948.ip-145-239-4.eu mongod[10347]: child process started successfully, parent exiting
Jun 04 06:08:01 ns3084948.ip-145-239-4.eu systemd[1]: Started MongoDB Database Server.
Hint: Some lines were ellipsized, use -l to show in full.
[root@ns3084948 ~]#