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  Convert time to Unix time


Unix time is defined as the number of seconds that have elapsed since midnight Coordinated Universal Time (UTC), 1 January 1970,not counting leap seconds. It is used widely in Unix-like and many other operating systems and file formats. It is neither a linear representation of time nor a true representation of UTC. Unix time may be checked on some Unix systems by typing date +%s on the command line. Sometimes it's a bit difficult to compare times stored in different applications or systems with ...

   UNIX time, Oracle DATE, conversion, timestamp     2013-01-19 09:04:17


  A Toast to C


At Cloudmetrx, we use a lot of C. So given the recent passing of UNIX legend Dennis Ritchie, the creator of the C language, we think a toast to C is only fitting.Our extensive reliance on C is especially unusual considering the other languages in our stack – Clojure, Node.js, and other hipster platforms. We aren't predisposed to using older, "venerated" technologies simply because they're older and venerated. But when it comes to high-performant computation, there's just nothing like C. Some w...

   C,Toast,C Language,Unix,Dennis ritchie,popularity     2011-10-24 11:21:32


  Carriage return and line feed


In programming and document editing, we may frequently encounter carriage return and line feed, i.e the well known CRLF.  Do you know about the history and difference of carriage return and line feed?Before computer came out, there was a type of teleprinter called Teletype Model 33. It can print 10 characters each second. But there is one problem with this, after finishing printing each line, it will take 0.2 second to move to next line, which is time of printing 2 characters. If a new char...

   Carriage return,Line feed,CR,LF,new line     2012-05-18 11:12:55


  Unix Philosophy


First, let me tell two stories.The first one is one Japan soap factory had a problem that they sometimes shipped empty boxes to the customer without soap inside. So they spend much time and money to invent a X-ray machine to check whether the soap box is empty.The same thing happens in a small factory which doesn't have too much money. The solution of them to solve this problem is they use a desk fan to blow the empty boxes out of the belt and into a bin.The second story is NASA finds that in sp...

   Unix Philosophy,Simple,Rules     2012-05-06 06:49:26


  Socket programming tips in Solaris


I sponsored a topic in stackoverflow.com, and hoped the programmers can share the socket programming tips in different UNIX flavors. But unfortunately, the responders are few. So I can only share my socket programming tips in Solaris at here (the Chinese version can be found there): 1. Use the following link options: "-lresolv -lnsl -lsocket";2. Solaris doesn't provide socket options: SO_SNDTIMEO and SO_RCVTIMEO(Why does Solaris OS define SO_SNDTIMEO and SO_RCVTIMEO socket options...

   C,Solaris,socket,     2014-05-09 23:01:03


  printf("goodbye, Dennis");


Dennis Ritchie, a father of modern computing, died on October 8th, aged 70EVERY time you tap an iSomething, you are touching a little piece of Steve Jobs. His singular vision shaped the products Apple has conjured up, especially over the last 14 years, after Jobs returned to the helm of the company he had founded. Jobs's death in October resembled the passing of a major religious figure. But all of his technological miracles, along with a billion others sold by Apple's competitors, would be mere...

   Memory,Dennis Ritchie,C,Father of C     2011-10-22 12:42:22


  What is good design?


Some quotes about good design from a Germany designer Dieter Rams in documentary "Objectified": Good design should be innovative Good design should make a product useful Good design is aesthetic design Good design will make a product understandable Good design is honest Good design is unobtrusive Good design is long-lived Good design is consistent in every detail Good design is environmentally friendly Good design is as little design as possible This makes me think ...

   Good design,Simplicity,Princiople,Metro     2012-05-09 06:48:11


  Understand diff in Unix


diff is an important tool program in Unix. It is used to compare differences of two files, it is the foundation for code version control. If you type : $ diff <file_before_change> <file_after_change> diff will tell you what's the difference between these two files. The result may not be so easy to understand, so now I will show you how to understand diff. 1. 3 formats of diff diff has 3 formats due to historic reasons. normal diff context diff unified diff 2. Demo files For easy d...

   diff,Unix,version control,git     2012-09-03 10:49:36


  When to use STDERR instead of STDOUT


Every process is initialized with three open file descriptors, stdin, stdout, and stderr. stdin is an abstraction for accepting input (from the keyboard or from pipes) and stdout is an abstraction for giving output (to a file, to a pipe, to a console). That's a very simplified explanation but true nonetheless. Those three file descriptors are collectively called 'The Standard Streams'. Where does stderr come from? It's fairly straightforward to understand why stdin and stdout exist, however ...

   UNIX,STDERR,STDOUT,Difference     2012-01-14 12:07:43


  Severe SSL 3.0 vulnerability to be released


According to The Register, another severe security vulnerability has been found in the widely used SSL v3 protocol. Until now, it's still in patch phase and the details of this vulnerability is expected to be released today. There are a few widely impacted security vulnerabilities revealed this year and they bring people's attention to the long existing security concerns. Previously, we have seen the HeartBleed issue and also the recently ShellShock issue. Both of them occur in popular libraries...

   SSL,Security vulnerability, The Register     2014-10-14 22:22:39