How to open a URL in a new window in JavaScript?

Posted on

How to open a URL in a new window in JavaScript? For example, to open a new window to browse “http://www.systutorials.com“. Open the URL in a new window: url = “http://www.systutorials.com”; window.open(url); Some browser will open the window in a new tab depending on the configuration. If you want to force the browser to open
Read more

How to force ssh client to authenticate using password on Linux?

Posted on

ssh client can use many authentication methods like password, keys. On a server, I set password-less log in with private/public key. Now, I want to try whether the new password is set correctly by log on using ssh. By default, the key-based authentication method is used again. How to force ssh client to authenticate using
Read more

How to allow websites’ .htaccess files in Apache2?

Posted on

How to allow websites to use .htaccess files in Apache2 web servers? The AllowOverride directive controls this: http://httpd.apache.org/docs/current/mod/core.html#allowoverride To allow AllowOverride in a directory, add the following rules to the /etc/httpd/conf/httpd.conf or similar configuration file for your apache installation: <Directory “/var/www/www.example.com”> Options FollowSymLinks # # AllowOverride controls what directives may be placed in .htaccess files.
Read more

How to enable SSH service on Fedora Linux?

Posted on

How to enable SSH service on Fedora Linux? By default, it seems ssh is not enabled. Fedora may not have sshd service installed/enabled by default. You will need to install and configure it by yourself. The following instructions is for Fedora 22 as an example. First, install the sshd server by # dnf install openssh-server
Read more

How to make Fedora Linux not clean some files in /tmp/?

Posted on

On my Fedora 20, I find that the system automatically clean up file under /tmp/. This is convenient. However, it cause some problems for some programs. For example, HDFS puts its DataNode pid file under /tmp/ by default like hadoop-hadoop-datanode.pid. After it is cleaned up, the hadoop-daemon.sh script will consider there is no DataNode running.
Read more

How to mount LVM volume from an external hard disk on CentOS?

Posted on

On Fedora, after inserting/plugging in an exteranl hard disk with LVM partitions on it, the partitions will appear under /dev like /dev/lvm-group/lvm-partition. However, on CentOS 6, the LVM volumes do not appear automatically. How to mount LVM partitions from an external hard disk on CentOS? What you need on CentOS is to activate the LVM
Read more

Good Cinnamon theme for Fedora 21 Linux?

Posted on

Any suggestion on good theme configuration for Fedora 21 Linux? My favorite combination of Window borders, Icons, Controls, Mouse Pointer and Desktop is as follows. All packages and themes are from Fedora repository or the Cinnamon repository. Remember to set the cursor theme for QT application like Google Chrome following: https://www.systutorials.com/4068/configuring-mouse-cursor-style-for-qt-applications-in-gnome-mate-desktop/ For this configuration, the
Read more

How to make Linux automatically reboot after a kernel panic?

Posted on

After a kernel panic, it is impossible to remotely connect to the Linux server to reboot it by SSH. How to make the panic kernel automatically reboot itself? Linux kernel has a nice feature that reboots itself after a timeout when a kernel panic happened. Usually, it is disabled by default. To turn it on,
Read more

How to enable RPM Fusion for CentOS 6.6?

Posted on

How to enable RPM Fusion for CentOS 6.6? Enable RPM fusion on RHEL 6 or compatible like CentOS: su -c ‘yum localinstall –nogpgcheck http://download1.rpmfusion.org/free/el/updates/6/i386/rpmfusion-free-release-6-1.noarch.rpm http://download1.rpmfusion.org/nonfree/el/updates/6/i386/rpmfusion-nonfree-release-6-1.noarch.rpm’ It will install https://fedoraproject.org/wiki/EPEL. If it fails to install EPEL automatically, you will need to install it manually. Reference: http://rpmfusion.org/Configuration

Basic iptables configuration for Linux

Posted on

What is a good basic iptables config? Basic rules needed: Allow incoming TCP to 22 for SSH but blocks all others. Allow outgoing TCP/UDP connections. You may consider using the following rules as a start: for tables in iptables ip6tables ; do # Flush existing rules $tables -F # Default policy $tables -P INPUT DROP
Read more

How to configure iptables on Linux Mint 17.1?

Posted on

How to configure iptables and make the configuration persistent across system restarting on Linux Mint 17.1? You can use the ‘iptables-persistent’ tool. To install iptables-persistency pachage: sudo aptitude install iptables-persistent The you can manipulate the iptables by the ‘iptables’ command. To save the current iptables rules: sudo /etc/init.d/iptables-persistent store It will store the rules for
Read more

How to pull your git tree after creating it on remote server

Posted on

Currently, I have created my branch dev-harry but I cannot pull it successfully as follows. harryxiyou@common_vm ~/forest/kvplus/kvplus $ git branch * dev-harry master rc harryxiyou@common_vm ~/forest/kvplus/kvplus $ git pull You asked me to pull without telling me which branch you want to merge with, and ‘branch.dev-harry.merge’ in your configuration file does not tell me, either.
Read more

How to dynamically attach a disk to running DomU in Xen?

Posted on

I want to attach a disk to a DomU. The Xen DomU is running and should not be rebooted. Hence, changing its configuration file is not an option. How to dynamically attach a disk to running DomU in Xen? To attach phy:vg_xen/vm-228-large to vm-228 as xvdb, run this on Dom0: # xl block-attach vm-228 phy:vg_xen/vm-228-large
Read more

How to change an running HDFS cluster’s replication factor?

Posted on

Now, I have a running HDFS cluster storing lost files. I want to change its default replication factor. How to change it? What will happen after it is changed? For example, I change from 2 to 3. Will HDFS automatically re-replicate the data chunks? First, the replication factor is client decided. Second, the replication factor
Read more

How to change number of replications of certain files in HDFS?

Posted on

The HDFS has a configuration in hdfs-site.xml to set the global replication number of blocks with the “dfs.replication” property. However, there are some “hot” files that are access by many nodes. How to increase the number of blocks for these certain files in HDFS? You can the replication number of certain file to 10: hdfs
Read more

How to boot Linux Mint to the console by default?

Posted on

How to boot Linux Mint to the console by default? (that is, the run level 3). 2 methods introduced here to boot Linux Mint to console/command line. Method 1 (may only work for earlier releases; check method 2 below): set kernel option. Edit /etc/default/grub and add text to GRUB_CMDLINE_LINUX_DEFAULT: GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash text” Then, re-generate grub
Read more

How to install no-ip update client on Linux Mint?

Posted on

How to install no-ip.com update client noip2 on Linux Mint 17? First, install the noip2 client: sudo su – cd /usr/local/src wget http://www.no-ip.com/client/linux/noip-duc-linux.tar.gz tar xzf noip-duc-linux.tar.gz cd no-ip-2.1.9-1 make make install Then, generate the configuration file noip2 -C Last, make noip2 daemon run at reboot crontab -e Add this line to crontab: @reboot /usr/local/bin/noip2 I’ve
Read more

How to set the data replication factor of Hadoop HDFS?

Posted on

How to set the data replication factor of Hadoop HDFS in Hadoop 2 (YARN)? The default replication factor in HDFS is controlled by the dfs.replication property. The value is 3 by default. To change the replication factor, you can add a dfs.replication property settings in the hdfs-site.xml configuration file of Hadoop: <property> <name>dfs.replication</name> <value>1</value> <description>Replication
Read more