The cut command is designed for simple field splitting, but it has a hard limitation: the delimiter must be a single character. cut –delimiter=”delim” -f 1,3 # Error: cut: the delimiter must be a single character This is a deliberate design choice. cut prioritizes speed and simplicity for common use cases like splitting on tabs,…
utop is an improved OCaml REPL with line editing, history, context-sensitive completion, and syntax highlighting. While powerful, its key bindings differ from standard GNU readline, which can be jarring if you’re used to standard shell behavior. Getting the key bindings list The simplest way to see all available bindings is to run the #utop_bindings directive…
When a program appends data to a file, you need to know how much space remains on the partition containing that file. This determines whether the file can grow or if you’re about to hit a capacity limit. Quick answer To find available space for a file, use df: df -B1 /mnt/logs/app-log.log | tail -1…
The nm command displays symbolic information from object files, libraries, and executables. It’s the standard tool for inspecting what functions and variables are defined or referenced in a static library (.a file). Basic usage List all symbols in a library: nm lib.a This outputs symbol names, but the default format can be hard to parse….
Modern Fedora systems keep multiple kernel versions available, but older kernels are tucked in a submenu rather than appearing as top-level GRUB2 entries. This requires a slightly different approach when setting them as your default boot option. Understanding the GRUB2 submenu structure When you run: grep menuentry /boot/grub2/grub.cfg | cut -d “‘” -f2 You’ll see…
When you’re fighting page limits — conference submissions, journal requirements, or just fitting content on a poster — reducing LaTeX’s default spacing is essential. Here are the practical approaches, from gentle to aggressive. Basic Spacing Adjustments Start with the most impactful changes. These target the whitespace around floats (figures, tables) and captions: \setlength{\textfloatsep}{1pt} % Space…
RHEL-based distributions only provide 64-bit Wine packages in their standard repositories. Many Windows applications—especially legacy software—require 32-bit Wine. Building Wine from source is the most reliable approach to get a working 32-bit installation alongside 64-bit support. Prerequisites and Resource Requirements Building Wine requires significant resources: ~2GB temporary disk space, ~500MB installed Compilation takes 20-40 minutes…
When you dock a laptop with an external USB keyboard, the built-in keyboard becomes a nuisance—it’s too easy to brush keys while typing and trigger unwanted input. Rather than disabling the keyboard at the BIOS level or physically disconnecting it, you can use the xinput tool to disable and re-enable it from within your Linux…
WordPress performance depends on three complementary caching layers: PHP bytecode caching (OPcache), page caching (WP Super Cache), and asset optimization (Autoptimize). Combined properly, they’ll cut your Time to First Byte in half and significantly improve Core Web Vitals. Enable OPcache in PHP OPcache caches compiled PHP bytecode in shared memory, eliminating parse and compile overhead…
Modern Linux systems use GRUB2 as the bootloader. You’ll set the default boot entry either through the configuration file or via command-line tools. View Available Boot Entries First, list all available GRUB2 menu entries: grep ^menuentry /etc/grub2.cfg | cut -d “‘” -f2 On UEFI systems, use /etc/grub2-efi.cfg instead. If you’re unsure which mode your system…
MPlayer and mencoder are obsolete. FFmpeg and mpv (the actively maintained fork of MPlayer) are the standard tools for video manipulation on Linux systems today. While some MPlayer syntax still works in mpv, FFmpeg is more performant, better documented, and handles modern codecs reliably. This guide covers practical tasks using FFmpeg and mpv, with mpv…