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How to Configure Scanner in an HP All-In-One Printer on Linux?

The hplip packages contains all the tools you need to set up the HP scanner. For scanning, you may use the sane and xsane tools. The tricky part to enable the scanner is carefully choose which driver to use from the hplip package. If you choose a non-suitable driver, only the printer will work and…

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SSD Enabled For DreamHost Shared Hosting: Simple Performance Measurement

SSD is common for VPS and PaaS virtual machines for higher I/O performance. Now, it is coming to shared hosting too. DreamHost states that “Now with solid state drives (SSDs), our standard web hosting loads pages 200% faster”. We ourselves are happy to know this performance improvement with the price kept the same. Good work,…

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Free VPNs for iPhone Users: OpenVPN + Ovpn Spider

VPNs are useful for testing viewing webpages from a remote location or visiting blocked websites. In this post, I will introduce a method for finding and using free VPNs on iPhone. Note that the VPNs are free and the providers are not identified. Hence, only use this method for visiting public webpages or keeping visiting…

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How to Make Chrome Accept Self-Signed Certificates on Linux

If your website uses a self-signed certificates, Chrome will show a warning every time and you need clicks to continue. In this post, I will introduce how to make Chrome accept self-signed certificates for sites on Linux. This post is made short on purpose and you need to search the Web and learn if you…

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Creating a Child Process using posix_spawn in C in Linux

The posix_spawn() and posix_spawnp() functions create a new child process from the specified process image constructed from a regular executable file. It can be used to replace the relative complex “fork-exec-wait” methods with fork() and exec(). However, compared to fork() and exec(), posix_spawn() is less introduced if you search on the Web. The posix_spawn() manual…

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Hadoop Installation Tutorial (Hadoop 2.x)

Hadoop 2 or YARN is the new version of Hadoop. It adds the yarn resource manager in addition to the HDFS and MapReduce components. Hadoop MapReduce is a programming model and software framework for writing applications, which is an open-source variant of MapReduce designed and implemented by Google initially for processing and generating large data…

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How to Configure iOS to Use Socks Proxy over SSH with a Linux/Unix Host

The socks proxy I created following Proxy Using SSH Tunnel works very well on both Linux and Windows. However, when I try to configure my iPhone and iPad with iOS, I find iOS does not support socks proxy in its settings interface. I don’t know why it is not added while socks proxy is indeed…

How to Copy Output of Commands in a Linux Terminal to X Selection or Clipboard

xclip is a tool to copy the copy the output of commands from a command line in a terminal to X selection or clipboard. It connects the command line interface and the X selections (clipboard) and is a very useful tool. For example, processing some text in vim in a terminal and then copying it…

Latex Cheat Sheet

Latest has many commands and it is not easy to quickly remember them all. Then, a cheat sheet will be very useful. Here is a collection of cheat sheets for Latex that I collected from the Web. Latex cheat sheet Latex cheat sheet by Winston Chang: Download latex cheat sheet. LaTeX Math Symbols https://web.archive.org/web/20190707092927/http://web.ift.uib.no/Teori/KURS/WRK/TeX/symALL.html

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GNU glibc Manual

“The C language provides no built-in facilities for performing such common operations as input/output, memory management, string manipulation, and the like. Instead, these facilities are defined in a standard library, which you compile and link with your programs. The GNU C library, described in this document, defines all of the library functions that are specified…

How to Connect to MySQL in JSP

We use tomcat as the container used for instructions in the post. 1) Download the driver mysql-connector-java-*.*.*-bin.jar and put it into WEB-INF/lib/, and remember to restart tomcat. 2) The example code as follows. String driverName=”com.mysql.jdbc.Driver”; String userName=”username”; String userPasswd=”password”; String dbName=”dbname”; String tableName=”tablename”; String url=”jdbc:mysql://localhost/”+dbName+”?user=”+userName+”&password=”+userPasswd; Class.forName(“com.mysql.jdbc.Driver”).newInstance(); Connection conn=DriverManager.getConnection(url); Statement statement = conn.createStatement(); String sql=”SELECT *…