Or simply put, easily switch between versions of NodeJS on any Linux based system. There are two most popular Node version managers. One, my personal favourite is n package, the other one is nvm.

n

For me the easiest way is to use n package. Just install whatever Node version your official distribution ships with.

sudo yum install nodejs

or, depending on what Linux you're using.

sudo apt-get install nodejs

Then install n as a global package.

sudo npm install -g n

/usr/local/bin/n -> /usr/local/lib/node_modules/n/bin/n
+ n@6.5.1
added 1 package from 4 contributors in 0.201s

Done, it was that easy. Now install the version of node you want to use:

sudo n lts <--- latest LTS official release
sudo n latest <--- latest official release
sudo n stable <--- stable official release
sudo n 10.16.0 <--- specific version

Execute n on its own to view your downloaded versions, and install the selected one.

n

    node/8.11.2
    node/10.14.2
    node/10.15.0
    node/10.16.0
  ο node/12.18.1

Use up/down arrow keys to select a version, return key to install, d to delete, q to quit

nvm

Run the official install script by executing one of below commands:

curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash

wget -qO- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash

Rerun Profile script to start NVM

source ~/.bashrc

Now nvm should be running and you can confirm it by running below

nvm

Node Version Manager (v0.35.3)

If everything went fine, make nvm use your currently installed Node version

nvm use system

Now using system version of node: v8.11.2 (npm v6.9.0)

List available versions using

nvm ls-remote

Install the latest release of node

nvm install node <--- latest version
nvm install 10.16.0 <--- specific version

If after exiting console and logging in again nvm is not a recognised command, you'll need to add source ~/.bashrc to your .profile or .bash_profile file to make sure it's automatically run on every login. A good explanation of what's going on, can be found here.

If you want to avoid situation when after server restart you have to start lots of services manually, a little thing like chkconfig would come in handy.
First you might want to take a look at a list of services handled by chkconfig:

chkconfig --list

You should see something like this:

mysql 0:off 1:off 2:on 3:on 4:on 5:on 6:off
named 0:off 1:off 2:off 3:on 4:off 5:off 6:off
sshd 0:off 1:off 2:on 3:on 4:on 5:on 6:off

To add for example mysql to autostart list simply type:

chkconfig --add mysql on

To remove a service from autostart list type:

chkconfig --del mysql

For full list of chkconfig options go here.

After installing memcached daemon, we have to install memcache PHP extension.

yum install php-pecl-memcache

or

apt-get install php5-memcache

If above is not an option try below method.

pecl install memcache

After successful installation add memcache.so extension to your php.ini file.

vim /etc/php.ini

Add this line:

extension=memcache.so

Restart web server

service httpd restart

Test out our installation.

<?php
$memcache = new Memcache;
$memcache->connect('localhost', 11211) or die ('Can\'t connect!');
$version = $memcache->getVersion();
echo 'Server version: '.$version;

You should see your server’s version number. If you see a blank page make sure that memcached daemon is working. If you’re getting "Can’t connect!" message despite running daemon try changing 'localhost' to '127.0.0.1'.

Install dependancy

Before we install memcached we need a dependency library libevent. Check for latest stable version at https://monkey.org/~provos/libevent/

cd /usr/local/src
wget http://monkey.org/~provos/libevent-1.4.13-stable.tar.gz
tar -xzvf libevent-1.4.13-stable.tar.gz
cd libevent-1.4.13-stable
./configure --prefix=/usr/local
make
make install
cd ..

Install memcached

Check for latest stable version at https://memcached.org/

wget http://memcached.googlecode.com/files/memcached-1.4.4.tar.gz
tar -xzvf memcached-1.4.4.tar.gz
cd memcached-1.4.4
LDFLAGS='-Wl,--rpath /usr/local/lib'
./configure --prefix=/usr/local
make
make install

More information about LDFLAGS https://en.wikipedia.org/wiki/Linker

Run memcached as a daemon

Basic options: d = daemon, m = memory, u = user, l = IP to listen to, p = port

memcached -u root -d

or

memcached -u root -d -m 512 -l 127.0.0.1 -p 11211

To stop daemon type

pkill memcached

Now we’re off to installing php extension memcache.

xmpppy is a Python library allowing you to send messages from your server to any Jabber enabled communicator.
Firstly download and unpack xmpppy to a local directory. Next go into the unpacked directory and run:

python setup.py install

Next you need a script that will do the sending. Use your favourite text editor to create file i.e.:

vim xsend.py

Just paste below script which was taken from original site. Create another jabber account that you’ll send messages from and remember to change values in line 20 to those new login details.

#!/usr/bin/python
# $Id: xsend.py,v 1.8 2006/10/06 12:30:42 normanr Exp $ 
import sys,os,xmpp,time
if len(sys.argv) < 2:
    print "Syntax: xsend JID text"
    sys.exit(0)

tojid=sys.argv[1]
text=' '.join(sys.argv[2:])

jidparams={}
if os.access(os.environ['HOME']+'/.xsend',os.R_OK):
    for ln in open(os.environ['HOME']+'/.xsend').readlines():
        if not ln[0] in ('#',';'):
            key,val=ln.strip().split('=',1)
            jidparams[key.lower()]=val
for mandatory in ['jid','password']:
    if mandatory not in jidparams.keys():
        open(os.environ['HOME']+'/.xsend','w').write('#Uncomment fields before use and type in correct credentials.\n#JID=romeo@montague.net/resource (/resource is optional)\n#PASSWORD=juliet\n')
        print 'Please point ~/.xsend config file to valid JID for sending messages.'
        sys.exit(0)

jid=xmpp.protocol.JID(jidparams['jid'])
cl=xmpp.Client(jid.getDomain(),debug=[])

con=cl.connect()
if not con:
    print 'could not connect!'
    sys.exit()
print 'connected with',con
auth=cl.auth(jid.getNode(),jidparams['password'],resource=jid.getResource())
if not auth:
    print 'could not authenticate!'
    sys.exit()
print 'authenticated using',auth

#cl.SendInitPresence(requestRoster=0)   # you may need to uncomment this for old server
id=cl.send(xmpp.protocol.Message(tojid,text))
print 'sent message with id',id

time.sleep(1)   # some older servers will not send the message if you disconnect immediately after sending

#cl.disconnect()

All you need to do now is to run the script 🙂 First run will create a file in your home directory which should contain username and password from line 20. Second run should accually send the message.

./xsend.py your_main_jabber@your_jabber.com Hello world!

Now set up your monitoring scripts that will send you jabber messages when something goes wrong.