Tag: RHEL

Linux User Group Management and Operations

Posted on by Eric Ma

Linux allows more than one users to log into the system to run processes/programs at the same time. In order to make this multi-user system work properly, Linux provides ways to isolate and protect users from each other and manage the permissions efficiently. One of the mechanism is user groups. Linux users may be grouped
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How to Install Wine 32-bit on CentOS 8

Posted on by Eric Ma

Since version 7, RHEL and CentOS only have 64 bit versions. For some reasons, it’s better to run many Windows applications under 32 bit wine. Like How to Install Wine 32-bit on CentOS 7, this post introduce how to install 32-bit Wine on CentOS 8. Most of the mechanisms are similar yet there are differences.
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How to autohide top and bottom panel in RHEL 7

Posted on by Eric Ma

How to autohide top and bottom panels in RHEL 7 while application is running I don’t think GNOME 3 or GNOME 3 classic has this function available or there any plugins that supports so. If you need this function that the panel can hide automatically, you may consider another desktop environment, such as MATE, that
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How to disable the fastestmirror yum plugin in CentOS 7 Linux?

Posted on by Eric Ma

How to disable the fastmirror yum plugin in CentOS 7 Linux? The fastestmirror function of yum is provided by the package `yum-plugin-fastestmirror`. However, because `yum` depends on it, the `yum-plugin-fastestmirror` package can not be removed. If you try to remove it, `yum` will report failures like. # yum remove yum-plugin-fastestmirror Loaded plugins: fastestmirror Resolving Dependencies
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How to make CentOS Linux to load a module automatically at boot time?

Posted on by Eric Ma

How to make CentOS Linux to load a module, say ixgbe, automatically at boot time? I am using CentOS 7. You can create a text file <some name>.conf in the /etc/modules-load.d/ and list the modules to be loaded there, one per line. The systemd-modules-load.service daemon will read these files and load the modules. Check more
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How to install aclocal on Fedora Linux?

Posted on by Eric Ma

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
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How to configure ifcfg-eth0 network scripts on Fedora/RHEL Linux?

Posted on by Eric Ma

How to configure the ifcfg-* network script files under /etc/sysconfig/network-script/ on Fedora/RHEL Linux? Following is a very typical ifcfg-eth0 file setting static IP/gateway/network mask: DEVICE=eth0 BOOTPROTO=none ONBOOT=yes NETMASK=255.255.0.0 IPADDR=192.168.1.151 GATEWAY=192.168.1.10 USERCTL=no More options are supported, here you can find a reference: Interface Configuration Files (a easier to read PDF from F15 doc).

How to make CentOS 6.6 power off the console screen automatically?

Posted on by Eric Ma

On CentOS 6.6, I find that it can make the screen (console, not X) blank after a while. However, it does not power the screen off. This usually work on Fedora or other releases. I guess this is caused by some configurations specific in CentOS 6.6. How to make CentOS 6.6 power off the console
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How to enable RPM Fusion for CentOS 6.6?

Posted on by Eric Ma

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

How to install vbetool on CentOS 6.6?

Posted on by Eric Ma

I found CentOS 6.6 does not ship vbetool in its default repositories, EPEL or RPMfusion. How to install vbetool on CentOS 6.6? First, download the source package from http://www.codon.org.uk/~mjg59/vbetool/ and unpack the package. Second, install needed packages: # yum pciutils-devel pciutils-devel-static libx86-devel During the building, it will try to find the libpci.a in a different
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Where are the Linux routing table entries stored on disk?

Posted on by Q A

I know the routing tables on Linux is in memory after being set. However, where are the routing table entries stored on disk? I mean where are the routing table is persistently stored so that the routing table can be reloaded like the iptables (under /etc/sysconfig/iptables on Fedora/RHEL/CentOS Linuxes). If the system uses the /etc/rc.d/init.d/network
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Building and Installing Linux Kernel from the Source Code in an Existing Linux OS

Posted on by Eric Ma

Building Linux kernel may sound a complex and geek-only thing. However, as Linux kernel itself has much less depended tools/packages compared to other software packages, it is quite easy to compile, build and install a Linux kernel from the source code in an existing Linux OS. Building Linux kernel is needed if you need to
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How to Install Wine 32-bit on CentOS 7

Posted on by Eric Ma

Since version 7, RHEL has only x86-64 versions. The same thing happens to CentOS 7. In CentOS 7/EPEL, there is only package for Wine x86-64. However, many Windows .exe files are 32-bit. Even there are 64-bit versions for some software, their installation file is 32-bit. And for some certain software such as Office 2007, 32-bit
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Additional Repositories for CentOS Linux

Posted on by Eric Ma

CentOS is a super solid Linux distro. However, its default repository’s packages are limited compared to Fedora. Even Fedora needs some additional repositories to have software packages for daily usage, such as MPlayer, ffmpeg. Fortunately, some community maintained repositories provides these software. In this post, we introduce theses additional common repositories and how to install
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Changing Systemd Boot Target in Linux

Posted on by Eric Ma

Many Linux distros, such as RHEL/CentOS 7, Fedora, Ubuntu 16, are now using systemd instead of init as the init system. It is common for Linux users to set Linux to boot to “GUI” or “Text” mode. The old way of changing ‘/etc/inittab’ for choosing Linux runlevels is not working for sytemd. This post will
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How to Set the Static IP Address Using CLI in Fedora/CentOS Linux

Posted on by Eric Ma

How to set the static IP address for CentOS 7/Fedora 22+ is introduced in this post. Here, we assume the Linux is using NetworkManager to manage the network. All steps are done as root. Find the interface you want to set the address Command ifconfig -a lists all interfaces. Find the interface name to set,
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Notes for Beginners of Software Development on Linux

Posted on by Eric Ma

Linux is a great platform for software development targeting servers or backends. In general, working on Linux is very productive. The problem that beginners on Linux face is the the learning curve is steep at the beginning. But believe me, after you get through the initial green steep learning step as in the figure below
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How to Run a Command Upon Files or Directories Changes on Linux

Posted on by Eric Ma

Doing actions upon changes of files and directories is very useful. Examples like compiling a project after the source code files are changed, sending emails after important configuration files are modified, building the PDF after a TeX file is modified. On Linux, the inotify-tools provide good support for trigger actions after changes. In this post,
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