parmeshwor11

# installing memcache in ubuntu

1. create a user and give sudo access
$ sudo adduser newuser

$ sudo adduser newuser sudo

or

$ sudo visudo

parmeshwor11

open new window : ctrl+N
open new window in incognito mode : ctrl+shift+N

open new tab : ctrl+t
reopen last tab you closed : ctrl+shift+t

open link in background tab : ctrl+ click link
opne link in foreground tab : ctrl+shift+ click link

go previous page in browsing history : backspace  or alt +  -->

parmeshwor11

1. check if pdo support is installed 
$php -i|grep PDO
output : 
PDO
PDO support => enabled
PDO drivers => mysql
PDO Driver for MySQL => enabled

if installed ouptut is like above else 
$sudo apt-get install php5-mysql;

parmeshwor11

Permutation of numbers with repetition :
n - total elements  , r - taken r at a time
nPr=nr

Permutation without repetition 

nPr = n!/(n-r)!

combination of numbers

parmeshwor11

Error:

MongoDB shell version: 2.6.4
connecting to: test
2014-10-14T21:25:38.484+0545 warning: Failed to connect to 127.0.0.1:27017, reason: errno:111 Connection refused
2014-10-14T21:25:38.487+0545 Error: couldn't connect to server 127.0.0.1:27017 (127.0.0.1), connection attempt failed at src/mongo/shell/mongo.js:146
exception: connect failed

Solution: 
go to