Start by viewing the GRUB menu entries that will be generated during the next boot: sudo grub-mkconfig | grep -E ‘submenu |menuentry ‘ This will output something like: menuentry ‘Ubuntu’ –class ubuntu –class gnu-linux –class gnu –class os $menuentry_id_option ‘gnulinux-simple-…’ { submenu ‘Advanced options for Ubuntu’ $menuentry_id_option ‘gnulinux-advanced-…’ { menuentry ‘Ubuntu, with Linux 6.8.0-45-generic’ –class…
View all virtual machines registered with VirtualBox: vboxmanage list vms Output example: “ubuntu-server” {a1b2c3d4-e5f6-7890-abcd-ef1234567890} “debian-test” {b2c3d4e5-f6a7-8901-bcde-f12345678901} “centos-prod” {d6c938d8-0bec-57f0-9fd3-8e395ba3d218} Each VM appears with its name and UUID. The UUID uniquely identifies the VM in VirtualBox’s database. List running VMs only See only active virtual machines: vboxmanage list runningvms This is useful when you have many VMs…
Static linking is essential when distributing OCaml binaries across systems without managing runtime dependencies. OCaml supports two main approaches: glibc-based static linking (which retains some dynamic dependencies) and musl-based static linking (producing truly portable binaries). Static Linking with glibc The simplest approach uses glibc with the -static flag passed to the C linker. Since OCaml…
Xen remains a solid hypervisor choice for specific workloads, though KVM dominates most Linux distributions today. This guide covers installing a paravirtualized DomU on Xen using modern tooling and Rocky Linux 9, which requires specific kernel parameters during installation. Why Paravirtualization Matters Paravirtualized guests communicate directly with the hypervisor rather than emulating hardware, resulting in…
Systemd replaced traditional init on most modern Linux distributions, shifting terminology from “runlevels” to “targets.” If you’re migrating from older systems, here’s the mapping: Runlevel Systemd Target Purpose 0 poweroff.target Shutdown 1 rescue.target Single-user mode 2, 3, 4 multi-user.target Multi-user, no GUI 5 graphical.target Multi-user with GUI 6 reboot.target Reboot The two targets you’ll use…
Before writing code, get comfortable with fundamental Linux commands. You’ll use these daily: File operations: ls, cd, cat, less Text search: grep, ripgrep (rg) Remote access: ssh, scp, rsync Session management: tmux or screen for persistent terminal sessions Shell: bash (default on most distributions), though zsh and fish are popular alternatives Start with built-in documentation….
Watching for filesystem changes and triggering actions is essential for development workflows—recompiling after source edits, restarting services when configs update, or running tests during coding. Linux’s inotify subsystem provides kernel-level file monitoring, and inotifywait makes it accessible from the command line. Installation Install inotify-tools on your system: Fedora/RHEL/CentOS: sudo dnf install inotify-tools Debian/Ubuntu: sudo apt…
GRUB2 configuration needs to be regenerated when you modify boot parameters, install new kernels, or adjust default boot entries. The process varies slightly between BIOS and UEFI systems, and between distributions, but follows a consistent pattern once you understand your system layout. Check Your System Firmware Type Before regenerating config, identify whether your system uses…
Modern Fedora (29+) uses firewalld by default instead of the legacy iptables service. If you’re working with an older system or one configured for iptables, the concepts here still apply, but you should first check what’s actually managing your firewall: systemctl status firewalld systemctl status iptables If firewalld is active, use firewall-cmd instead. For iptables-based…
IPv6 is enabled by default on most Linux distributions. While IPv6 adoption has grown, there are legitimate reasons to disable it: some legacy applications don’t handle dual-stack networks well, it can complicate firewall rules, or you might be operating in an environment that doesn’t support it. Disabling IPv6 requires kernel-level configuration through sysctl. Using sysctl…
Fedora has evolved its hostname management over the years. Modern versions use systemd and the /etc/hostname file, while older releases relied on /etc/sysconfig/network. Here’s how to handle both scenarios. Using hostnamectl (Recommended) The most straightforward method on current Fedora is using hostnamectl, which handles hostname changes through systemd: sudo hostnamectl set-hostname newname.example.com For a hostname…
IPv6 is enabled by default on most Linux distributions. While IPv6adoption has grown, many environments still rely primarily on IPv4, and disabling IPv6 can simplify networking configurations or resolve compatibility issues. Quick Method: Disable via modprobe The most straightforward approach is to prevent the IPv6 kernel module from loading: echo “options ipv6 disable=1” >> /etc/modprobe.d/disable-ipv6.conf…