Update on Oct. 9, 2014: You should be aware of the possible security problems of blowfish and it is suggested not to be used. Instead, you may consider ChaCha20 as suggested by Tony Arcieri. To use this with OpenSSH, you need to specify the Ciphers in your .ssh/config files as chacha20-poly1305@openssh.com possibly with another default
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Category: Tutorial
Accelerating WordPress with WP Super Cache, Opcache and Autoptimize
Posted onWordPress can be very fast after some effort on performance optimization with the help from its plenty of plugins. Possible ways include using cache to cut down the number of database queries, improves HTML/JavaScript/CSS code, and optimizing PHP’s performance with opcode cache. In this post, we introduce how to speed up WordPress with OPcache, page
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Making Emacs Start Up Faster
Posted onI use Emacs in terminals and start/close Emacs frequently as needed like in a file checking-editing-closing loop. However, Emacs seems take some time to start up especially some heavy modes are used. How to make Emacs start up faster? (If you just want the solution/script first, find the command in the summary section.) My solution
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Vim Howtos and Tips
Posted onVim is a fast and handy editor on *nix systems. Like Emacs, Vim has a steep learning curve as you get constantly get new things. However, the effort deserves it as you efficiency is highly improved. Here, I summarize the tips and howtos I learned using Vim. Some previous posts on vim are tagged with
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How to Set Up A Gitolite Git Server – A Ten-Minute Tutorial
Posted onI ever introduced seting up git server using SSH or gitosis. However, gitolite is the way to go for managing git servers if you want an lightweight authentication layer. gitolite provides many very usefull features which can control each user’s right on each branch. I set up one gitolite git server and am very happy
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RAII-like Error Handling and Resource Management in C
Posted onError handling and resource management are pervasive in programs. RAII originated in C++ is great. With RAII, it is much easier to write easy-to-read code that allocats/deallocats resources in the constructor/destructors. By representing a resource with a local object, we are sure that local object’s destructor will release the resource and will not forget to
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How to Connect to Remote Servers by VNC on Windows
Posted onSoftware you will need 1, Putty 2, Real VNC viewer 3, twm (lightweight desktop). On fedora (centos, redhat): sudo yum install twm (on other distros, you may need other commands, or download source code and install it). Specific steps 1, Enter your Host name and port in putty. 2, Set port forwarding in putty Tunnels.
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PHP Photo Gallery Scripts Requiring No Database
Posted onIt is nice to set up some photo gallery on the web and share with friends and family. Some online services are good and convenient. But if you want to host it on your own domain and control them by yourself, there are also many scripts available. Usually, we want the script simple to use
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Statically Linking C and C++ Programs on Linux with gcc
Posted onBefore statically linking you C and C++ programs, you should be aware of the drawbacks of the static linking especially with glibc. There are some good discussions already: with glibc you’re linking static programs which are not really static and some others here and here. That said, you can choose to statically link C and
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Auto Indenting for OCaml Code in Vim with ocp-indent
Posted onThe built-in indenting in Vim for OCaml seems not very good. How to set up auto indenting for OCaml code in Vim? ocp-indent works very well for me. This posts introduces how to configure Vim to use ocp-indent to automatically indent/format OCaml code. First, install ocp-indent after installing opam: $ opam install ocp-indent Second, configure
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How to Find Out Failed Disks’ SATA Ports in Linux
Posted onThe Linux disk names (e.g. sda1, hdb3, etc.) are not reliable—they may be changed if there are hardware changes, such an adding or removing a disk. Additionally, the order for the Linux device names is not always the same as the order of SATA poets. For example, the disk connected to SATA port 0 (first
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Making Ports Used by NFSv3 Server Static
Posted onThe ports used by NFS server can be dynamically assigned by rpbind to any higher number. We need to fix the ports used by NFS server to configure firewall or port forwarding mechanism. The ports used by NFS server and how to fix these ports will be introduced in this post. There are seven ports
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SSH Port Forwarding on Linux
Posted onPort forwarding (or tunnelling) is a method to forward one network traffic to another. We will introduce how to forward ports using SSH tunnel in this post. A simple example Let’s start with a simple and useful example: we want to forward local port 8080 to server:port. We can easily do this by using ssh
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How to Install ATI fglrx Driver on Fedora Linux
Posted onUpdate on Nov. 18, 2012: ATI fglrx driver works well on Fedora 17 with GNOME 3 Shell. Should work well with later releases. Great driver, ATI! Update on Nov. 29, 2011: ATI fglrx driver works on Fedora 16 with GNOME 3 Shell with Catalyst driver 11.11 (xorg-x11-drv-catalyst-11.11). Update on Oct. 9, 2011: GNOME 3 shell
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Managing Xen Dom0′s CPU and Memory
Posted onThe performance of Xen’s Dom0 is important for the overall system. The disk and network drivers are running on Dom0. I/O intensive guests’ workloads may consume lots Dom0′s CPU cycles. The Linux kernel calculates various network related parameters based on the amount of memory at boot time. The kernel also allocate memory for storing memory
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Linux UDP Programming Tutorial
Posted onUDP has its advantages over TCP, such as being relatively lightweight and receiving one packet per read call (recvmsg), although the programmers need to handle related issues, such as packet lost and out-of-order packets delivery. This post gives information and references on how to write UDP programs in a C/Linux environment. What is UDP Check
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How to Measure Time Accurately in Programs
Posted onIt is quite common to measure the time in programs using APIs like clock() and gettimeofday(). We may also want to measure the time “accurately” for certain purposes, such as measuring a small piece of code’s execution time for performance analysis, or measuring the time in time-sensitive game software. It is hard to measure the
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How to Bypass Bad fstab Failure When Booting Linux
Posted onIf /etc/fstab file is created with errors or the hardware configuration changes such as adding hard disks, Linux will boot into failure state. We can bypass the fstab failure by adding booting parameters to Linux. We can do this in two methods: Method 1: Boot to single user mode When booting into single user mode,
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Effective Anti-Spam in WordPress with Plugins
Posted onWordPress has a very rich set of plugins and a combination of them can make anti-spam in WordPress quite easy. Here is a list of plugins that can help prevent spammers from registering spam account (if the site allows registration of new users) and posting spam comments. Anti spam comments Use the Akismet WordPress plugin.
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How to Configure iOS to Use Socks Proxy over SSH with a Linux/Unix Host
Posted onThe 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
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