If we want to change the tick time for Linux Kernel, we need to change CONFIG_HZ parameter in Linux Kernel. Do we have other better ways to change it rather than compiling Linux Kernel. Please ignore the way to add ‘divider=10’ in grub config file because it is limited only for RH/CentOS distros. Zhiqiang, please…
My Ubuntu boots to GUI mode by default. How to make Ubuntu Linux boot to text mode? If you are using Ubuntu older than 16 such as Ubuntu 14.04: Edit /etc/default/grub Change GRUB_CMDLINE_LINUX=… to GRUB_CMDLINE_LINUX=”text”. Backup your old grub config`$ sudo cp -n /etc/default/grub /etc/default/grub.bak-date +%s ` Update grub$ sudo update-grub If you are using…
Firefox on CentOS7 does not have Flash enabled by default. How to install Flash Player plugin on CentOS 7? You may follow this tutorials to build a freshwrapper based flash plugin for Firefox on CentOS 7. If you don’t want to build it by yourself, you may download the pre-built .so from from this repository.
I find the rtl8192cu wireless adapter driver on CentOS 7 is quite unstable. After running a while, the connection will disappear. How to make it stable? There is a bug in some hardware where the device never wakes back up. You may try disabling the power management by putting a file 8192cu-disable-power-management.conf under /etc/modprobe.d/: #…
I tried to build a project while it reports: # ./autogen.sh Can’t exec “aclocal”: No such file or directory at /usr/share/autoconf/Autom4te/FileUtils.pm line 326. autoreconf: failed to run aclocal: No such file or directory How should I handle this? How to install aclocal? yum install aclocal shows: No package aclocal available. Error: Unable to find a…
Hello, I have installed Xen4Centos on Centos7, having single NIC card with bridge network and have two VMs on that. In one VM, I want to add two static IP one for webserver and one for mail server. So I have created IP alias in guest VM, it was created but it was not pinging…
PARSEC is the most important CPU-bound benchmark for systems. It is huge and hard to install because it needs lots of 3-part libs. PARSEC download link for 3.0 version: http://parsec.cs.princeton.edu/download.htm#parsec I remembered I added the answer yesterday night but I could not see the answer currently. Anyway, let me add the answer again after I…
NAS benchmark link: http://www.nas.nasa.gov/publications/npb.html For Ubuntu, remember to install gfortran (sudo apt-get install gfortran) and change config/make.def to install NAS benchmark. Other distros are similar.
I already have PHP and nginx installed and running on my on centOS 6.7. Please guide me, how can install glibc, glibc-common and GD libraries independently on my centOS 6.7 without crashing my system? I am not sure how you installed PHP and nginx. If they are installed from CentOS6.7’s Yum repository, you may install…
In Golang, how to convert a string to unicode rune array and do the reverse way? Convert string s to a rune array: runes := []rune(s) Convert a rune array runes to string: str := string(runes)
In Golang, the fmt.Println() is convenient to print to STDOUT. But how to print string to STDERR? In Go os package, “Stdin, Stdout, and Stderr are open Files pointing to the standard input, standard output, and standard error file descriptors.” So, you can use the WriteString function on File on os.Stderr to print string to…
In Golang, fmt.Println(err) can print out the error err. But how to convert an error to a string explicitely? In Go, the error type is an interface type that has an interface type error interface { Error() string } An error variable represents any value that can describe itself as a string. Ref: https://golang.org/pkg/builtin/#error So,…
The dmesg results from newer Linux kernels show the timestamps. It seems the time in seconds since the kernel start time. How to convert the dmesg timestamps to the real time on Linux? The dmesg timestamp is the time in seconds since the kernel starting time. Later dmesg has an -T option: -T, –ctime Print…
In Node.js, how to import functions from another JavaScript file like source common.sh in Bash? In the .js file to be imported such as ‘common.js’, organize functions to be exported like module.exports = { func1: function () { // func1 impl }, func2: function () { // func2 impl } }; In the other .js…
In the Go programming language, How to process a file line by line? An equivalent piece of Bash code could be while read line ; do echo $line done < ./input.txt You can make use of the bufio package’s Scan(). // open the file filepath f := os.Open(filepath) // create a scanner fs := bufio.NewScanner(f)…
In Go, how to create a Reader from a string? Many APIs use a Reader as its input. In Go, the strings.NewReader(s) library function creates a Reader from a string. Check the doc at: https://golang.org/pkg/strings/#NewReader
How to grep a tab on Linux? Including ‘t’ seems not working. grep can grep tabs. The problem is likely the tab is not passed to grep. If you are using Bash, you can use ANSI-C quoting to pass the “tab” to grep: $ grep $’t’ file.txt Or, use Perl-style regex (only for GNU grep)…
How to get the full path and directory of a Makefile itself like finding Bash script’s own path? This 2 lines in Makefile get the full path and dir of the Makefile itself: mkfile_path := $(abspath $(lastword $(MAKEFILE_LIST))) mkfile_dir := $(dir $(mkfile_path)) The piece of code gets you Makefile, finds its absolute path and the…
How to choose a key used rather than the default ~/.ssh/id_rsa when ssh to a remote server for a specific host? You have at least 2 choices for choosing the key used by ssh. Taking ~/.ssh/key1 and user@example.com as the example here. Method one, specify the key in command line with the -i option of…
how to use pc internet on iPhone 4s wia usb cable, pc is of window 8 and in network setting its not showing of connection of I phones network I ever wrote a tutorial at http://www.systutorials.com/136003/iphone-connecting-internet-using-windows-pc-network-through-usb-cable/ . But please be aware that it worked only on specific OS combinations. So, I am not sure whether…