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Showing posts from February, 2013

Network performance testing in Linux

IPERF is a network speed testing tool. It is reliable if you have two servers, and you want to measure network speed between them.

It can be installed using yum
# yum install iperf

For testing, one iperf instance runs as a server on one server and another iperf instance runs as a client on the other server.

For running iperf as a server
# iperf -s
Server listening on TCP port 5001

And for running iperf as a client
# iperf -c
Client connecting to, TCP port 5001 TCP window size: 16.0 KByte (default) 

[3] local port 47326 connected with port 5001 
[ID] Interval Transfer Bandwidth 
[3] 0.0-10.0 sec 267 MBytes 228 Mbits/sec

What is OpenID

OpenID is an open standard that allows users to be authenticated by certain co-operating sites using a third party service, eliminating the need for webmasters to provide their own ad hoc systems and allowing users to consolidate their digital identities.

Users may create accounts with their preferred OpenID identity providers, and then use those accounts as the basis for signing on to any website which accepts OpenID authentication.

Toad for Cloud Databases

Toad for Cloud Databases supplies SQL-based interface that makes it easier than ever for generating queries, migrating, browsing, and editing data, as well as create reports and tables in a common SQL view. It’s easy to load and export data from cloud databases to external data sources.
Puts NoSQL databases within your reach even if you’re an RDBMS developer or DBA Supports business decision making with fast access to cloud data Supports ANSI-standard SQL issued against cloud datasets Speeds accurate query generation through the query builder Lets you browse data and edit in-place Helps you create “tables” or their logical equivalent Supports DML SQL (UPDATE, INSERT, DELETE statements) Loads data from and exports data to a variety of external data sources, including RDBMS Provides assistance for deploying and managing Amazon EC2 instances

Linux bash string manipulation

Length of a string${#str} str="abcdefg" echo ${#str} #gives output 7
Substring extraction ${str:pos} extracts substring from $str at $pos str="abcdefg" echo ${str:2} #gives output cdefg
${str:pos:len} extracts substring from $str at $pos length of $len str="abcdefg" echo ${str:2:3} #gives output cde
Substring Removal${str#substr} removes shortest match of $substr from front of $str str="abcdefgabcdefg" echo ${str#a*c} #gives output defgabcdefg
${str##substr} removes longest match of $substr from front of $str str="abcdefgabcdefg" echo ${str##a*c} #gives output defg
${str%substr} removes shortest match of $substr from back of $str str="abcdefgabcdefg" echo ${str%b*g} #gives output abcdefga
${str%%substr} removes longest match of $substr from back of $str str="abcdefgabcdefg" echo ${str%%b*g} #gives output a