On a Linux box, we may allow non-root users mount and umount certain disks, such as /dev/sde1. How to allow non-root users on Linux to mount and unmount disks? Please check the tutorial at Controlling Filesystem Mounting on Linux by Playing with /etc/fstab: Allow non-root users to mount and unmount filesystems.
Some entries in /etc/fstab may not not critical for booting Linux or even not available until Linux has booted. How to avoid the failures or unavailability of some mounting entries in /etc/fstab blocking the boot process of Linux? Please check the tutorial at Controlling Filesystem Mounting on Linux by Playing with /etc/fstab: Allow non-root users…
How to make fdisk -l display partition sizes by bytes instead of sectors? fdisk does not have such options as far as I know. However, good news is that you can use parted: # parted -l It will print partition info like # parted -l Model: Linux device-mapper (linear) (dm) Disk /dev/mapper/fedora_vm235-swap: 2164MB Sector size…
I want to kick off a user such as “bob” on a Linux box which I managed remotely. How to do this? bob may log on the Linux box by various ways: Log on the screen on the Linux box (locally) with a X server. Log on remotely by a ssh shell. Log on by…
How to capture camera photo/video using MPlayer on Linux? You can watch the video from the camera by MPlayer: # mplayer tv:// Note that you need the root privilege to play the tv://. You can use mplayer to capture photos by: # mplayer -vo png -frames 3 tv:// If will store files 0000000{1..3}.png in the…
Grub fails to boot with Windows 8 UEFI after installing Fedora 20. The Grub entry for Windows 8 is: menuentry ‘Windows Boot Manager’ { chainloader /EFI/Microsoft/Boot/bootmgfw.efi boot } How to fix it? The set root= is missing. You probably can fix this by specifying the root manually: menuentry ‘Windows Boot Manager’ { insmod part_gpt set…
One of the most common causes of UDP data gram lost on Linux is an undersized receive buffer on the Linux socket. How to enlarge Linux UDP buffer size? On Linux, you can change the UDP buffer size (e.g. to 26214400) by (as root): sysctl -w net.core.rmem_max=26214400 The default buffer size on Linux is 131071….
How to exclude users from appearing in the GDM login screen of Gnome 3? There is a long-time bug related to this ( https://bugzilla.redhat.com/show_bug.cgi?id=723708 ) which causes that the /etc/gdm/custom.conf has no effect. The closes workaround I find working on Fedora 20 is to totally disable listing of users (run as root): cat > /etc/dconf/db/gdm.d/01-mysettings…
I am using Fedora 20. I installed the rpm from Oracle for the Oracle JDK. How to set up the environment so that the Java environment is Oracle JDK instead of the OpenJDK? The Oracle JDK is install to /usr/java/ directory. On my Fedora 20, it looks like this: $ ls /usr/java -l total 4…
How to add header footer in directory listing in Apache (httpd)? In the web directory’s .htaccess file: Options +Indexes IndexOptions FancyIndexing VersionSort NameWidth=* HTMLTable Charset=UTF-8 HeaderName /header.html ReadmeName /footer.html IndexIgnore header.html footer.html .htaccess header.html and footer.html are under the website root directory (not the Linux root).
How to manually set the boot entry for Windows in grub2? Suppose that your Windows is installed on the first partition of the first disk (hd0,1) (yes, it’s right, that is (hd0, 1) if your distribution has not modified grub2’s default behavior) in NTFS format. You can boot your Windows in grub2 by: insmod ntfs…
iptables is plain old good. How to enable it after I disable firewalld? First, install the iptables-services package as root: # yum install iptables-services Then, start iptables service as root: # touch /etc/sysconfig/iptables # touch /etc/sysconfig/ip6tables # systemctl start iptables # systemctl start ip6tables # systemctl enable iptables # systemctl enable ip6tables
How to change the fonts of gnome-shell for gnome3? Like the system bar. The fonts of gnome-shell is described in its own theme. For the default gnome-shell, you need to edit the file as root: /usr/share/gnome-shell/theme/gnome-shell.css Right, it is a css file. Find the font-family keyword and change the corresponding fonts. Then you can restart…
How to install WordPress in a sub directory while working for the whole site? Putting the WordPress files in the root directory seems messy. A method is introduced here: http://codex.wordpress.org/Giving_WordPress_Its_Own_Directory The process to move WordPress into its own directory is as follows: Create the new location for the core WordPress files to be stored (we…
Installing Fedora 19, Error “you have not created a bootloader stage1 target device” . It seems appear from Fedora 15: http://forums.fedoraforum.org/showthread.php?t=271743 This can be solved by adding noefi nogpt to the kernel parameters when booting the Linux for installation in grub as follows. Note: the “_” between nogpt and root is the cursor, not the…
How to force Linux to reboot when the reboot command does not work. Enable the use of the magic SysRq option: # echo 1 > /proc/sys/kernel/sysrq Reboot the machine: # echo b > /proc/sysrq-trigger Even if you could not log on the system but sshd is working, you can force the Linux to reboot by:…
I made some changes to /etc/sysctl.conf. I know it will take effect next time Linux boots. However, how to make the changes to sysctl.conf take effect without rebooting Linux? You can force Linux to reload the new configuration in /etc/sysctl.conf by: execute the following command as root: sysctl -p For more details, check the manual…
I made some changes in my local copy of the svn repository. I have not committed and updated the server yet. Now I want to discard my updates. How to revert my changes in my local copy of the repository? To discard current updates, run this in the root directory of the repository: svn revert…
How to disable all swaps on Linux to force the application/kernel use the physical memory? To diable all swaps on Linux, run this command as root: # swapoff -a -a means all swaps. Similarly, to enable all swaps on Linux: # swapon -a
When developing a C++ project, debugging is an essential part of the process, as it allows you to identify and fix issues in your code. If you’re using CMake to build your project, it’s crucial to know how to enable debug mode to take advantage of debugging tools like gdb. In this post, we’ll walk…