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alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
config_directory = /etc/postfix
inet_interfaces = all
local_recipient_maps = $virtual_mailbox_maps
mailbox_size_limit = 0
milter_default_action = accept
mydestination = localhost

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#Linux Environment Variables

##Current Environment Variables You can list all the currennt environment variables using the env command.

XDG_VTNR=7
SSH_AGENT_PID=2030
XDG_SESSION_ID=c2
XDG_GREETER_DATA_DIR=/var/lib/lightdm-data/leo

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#Linux Screen Screen is a handy utility to allow multiple tabs or split screens in text based terminal. It is particularly useful for connecting over ssh. For example, you could run a long running task like compiling etc and continue working in another screen. It can be installed from:

sudo apt-get install screen

Command include:

Ctrl-a c   #Create a new terminal
Ctrl-a n   #Cycle through the terminals available

Ctrl-a d #Exit screen

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#Linux - Logs To view the log messages in the memory queue use:

dmesg 

or dmesg | less

Most logs in Ubuntu are stored in /var/log. To access the system log use:

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#Android Studio - Installing To install android studio:

sudo apt-add-repository ppa:paolorotolo/android-studio
sudo apt-get update
sudo apt-get install android-studio

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#MongoDB Indexes There are 5 different index types supported in MongoDB.

1. Regular (B-Tree) - supports indexes on a single or multiple fields
2. Geo - supports indexing on a geographical location (useful for finding locations nearby)
3. Text - Allows for search engine like full text searching
4. Hashed - This is used primarily used for sharding as it evenly distributes the hashes rather than clustering them.
5. Time to Life - This supports expiring based on a document date field

##Create Index

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#MongoDB - JavaScript Since a query may return a large number of records which is too large for the client, the find returns a cursor instead of the data. This cursor can be assigned to a variable.

var vendorCursor = db.vendors.find();

You can see the size of the cursor using:

vendorCursor.size();

You can check to see if there is more data after the current cursor point in the data set using:

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Haversine - Distance between two points

// haversine
// By Nick Justice (niix)
// https://github.com/niix/haversine

var haversine = (function() {

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#JavaScript - Get Unique Elements

var test = ["Naas", "Newbridge", "Dublin", "Naas"]

> test
[ 'Naas',
  'Newbridge',
  'Dublin',

'Naas' ]

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#Ubuntu Terminal Color

R 48
G 10
B 36

H 319
S 79
V 19