Line number displays in Emacs can feel cramped without proper spacing. Modern Emacs provides built-in control over line number formatting and width—no external packages needed. Using display-line-numbers-mode display-line-numbers-mode is the standard in Emacs 25+ and should be your default choice. It’s faster and more maintainable than the older linum-mode. Enable it globally: (global-display-line-numbers-mode t) To…
Backing up a complete IMAP account with thousands of messages across nested folders requires automation to preserve folder structure and avoid manual errors. This guide covers three modern tools and provides detailed setup for the most flexible option. Choosing your backup tool offlineimap — Most flexible for complex folder structures and label handling. Active maintenance…
Emacs startup time matters when you’re opening files frequently from the command line or in scripts. A few targeted optimizations can reduce perceived startup overhead from seconds to near-instant. Run Emacs as a daemon with emacsclient The most effective optimization is the server/client architecture. Start Emacs once as a daemon, then reuse that instance for…
When the Scala compiler emits warnings like deprecation notices, you need to pass compiler flags to see the details. The solution is to configure scalacOptions in your sbt build. Session-Only Configuration During an interactive sbt session, add options temporarily: set scalacOptions += “-deprecation” This applies only to the current session and is lost after reload…
If you’re using the AddThis Welcome Bar with WordPress, you may see an unwanted gap appearing at the top of your page. This happens because AddThis injects a placeholder div that reserves vertical space: <div class=”addthis_bar_placeholder” style=”height: 46px;”></div> The 46px height creates a visible gap that disrupts your layout, especially on themes with fixed headers…
When a disk fills up or you’re doing a cleanup pass, finding the biggest files quickly saves a lot of time. Here are the practical approaches on Linux. Top 10 largest files in the current directory du -ah –max-depth=1 | sort -rh | head -n 10 Breaking this down: du -ah shows sizes for all…
GNOME Shell in GNOME 3 uses a specific font for the top bar, activities overview, and system notifications. You can customize these fonts using GNOME Tweaks or dconf to match your preferences. Using GNOME Tweaks (Recommended) # Install GNOME Tweaks sudo dnf install gnome-tweaks # Fedora sudo apt install gnome-tweaks # Ubuntu Open GNOME Tweaks…
Broken symbolic links accumulate over time and can cause confusion or errors when scripts rely on their targets. Identifying and cleaning them up is a regular maintenance task. Basic approach Use find with the -xtype l test to locate broken symlinks: find /path/to/directory -xtype l The -xtype l flag specifically matches symbolic links that point…
When managing user accounts on a cluster or application, you’ll often need to generate temporary passwords programmatically. Here’s a practical approach using Scala’s built-in utilities. Basic implementation with scala.util.Random For non-security-critical use cases, here’s a straightforward generator: def randomString(len: Int): String = { val rand = new scala.util.Random() val chars = “0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz” (0 until len).map(_…
This is fundamentally a decision about display technology and your reading habits. Here’s what you need to know. Display Technology The standard Kindle uses e-ink technology with a backlit display that requires external light sources — sunlight, a lamp, or overhead lighting. It’s readable but not ideal for low-light conditions. The Paperwhite adds a front-lit…
When you need to rsync against hosts behind NAT gateways or port-forwarded SSH services, the standard port 22 won’t work. The solution is the -e flag, which lets you specify a custom SSH command with your desired port. Basic usage Use -e to pass custom SSH arguments: rsync -avxP –delete -e “ssh -p 13022” username@example.com:/remote/path/…
By default, libvirt stores VM images as files in /var/lib/libvirt/images/. While functional, this approach limits flexibility. LVM (Logical Volume Management) provides better control over disk space, snapshots, and performance tuning. Using LVM volumes as libvirt storage pools lets you manage VM storage like block devices rather than files, giving you faster provisioning, atomic snapshots, and…
Linux systems can have multiple timer sources available, and the kernel selects one as the active clocksource. Understanding what’s available and how to view or change the current source is essential for performance tuning and troubleshooting timing-related issues. View the Current Timer Source Check which clocksource is currently in use: cat /sys/devices/system/clocksource/clocksource0/current_clocksource This will output…
When your OCaml program crashes with Fatal error: Exception “Stack_overflow” but doesn’t tell you where the problem originated, you need to enable backtrace reporting. The process is straightforward but requires recompilation. Enable Debug Symbols and Backtraces First, recompile your program with the -g flag to include debug information: ocamlopt -g -o myprogram myprogram.ml If you’re…
Trailing spaces and tabs at the end of lines are common annoyances in source code and configuration files. They’re invisible, waste space, and can cause issues with certain tools or version control systems. Here’s how to remove them efficiently. Using sed The most straightforward approach with sed: sed ‘s/[[:space:]]*$//’ your_file > your_file.tmp && mv your_file.tmp…
Xen HVM (Hardware Virtual Machine) guests require a configuration file that defines virtual hardware, networking, and boot parameters. Here are practical examples for common scenarios. Installation Configuration Use this configuration when installing a guest OS from an ISO: name=”10.0.1.235″ vcpus=2 memory=2048 shadow_memory=8 disk=[‘file:/lhome/xen/vm-10.0.1.235/vmdisk0,xvda,w’, ‘file:/lhome/Linux-x86_64-DVD.iso,xvdc:cdrom,r’] vif=[‘bridge=xenbr0′] kernel=’/usr/lib/xen/boot/hvmloader’ builder=’hvm’ device_model=’/usr/lib64/xen/bin/qemu-dm’ vnc=1 vnclisten=”0.0.0.0″ vncpasswd=’your-secure-password’ on_reboot=’restart’ on_crash=’restart’ Key points…
You have an LVM physical volume (PV) you need to remove from a volume group (VG), but the data needs to be preserved and moved to other available PVs. This is a straightforward but important operation that requires careful execution. Prerequisites Before starting, verify: The VG has sufficient free space on remaining PVs to accommodate…
When you need to format an integer with leading zeros in bash, printf is the standard approach. This is useful for generating zero-padded IDs, filenames, or any formatted output. Using printf The basic syntax mirrors C’s sprintf: n=42 str=$(printf “%08d” “$n”) echo “$str” # Output: 00000042 Here, %08d means: %d — format as decimal integer…
Converting LaTeX documents to HTML is useful for web publishing. Two main tools handle this conversion effectively: htlatex and latex2html. Both produce valid HTML output, though they have different strengths and limitations. Using htlatex htlatex is part of the tex4ht package and is generally more robust for modern LaTeX documents. Installation: On Fedora/RHEL: sudo dnf…
Java Runtime Environment (JRE) is required to run Java applications on Linux. On x86-64 systems, you have several installation options ranging from open-source to Oracle’s commercial builds. Install OpenJDK (Recommended) OpenJDK is the open-source implementation and is available in all major Linux distributions: # Fedora / RHEL / Rocky Linux sudo dnf install java-17-openjdk #…