When compiling MapReduce jobs against a Hadoop installation, you need to include the correct classpath to resolve Hadoop dependencies. The yarn classpath command handles this automatically. Getting the classpath Run this command to output the full classpath: yarn classpath If yarn isn’t in your $PATH, use the full path: $HADOOP_HOME/bin/yarn classpath Replace $HADOOP_HOME with your…
Remapping Caps Lock to Control is a worthwhile investment if you spend significant time in Emacs or vim. Your pinky will benefit from years of reduced strain. Desktop Environment Settings (Easiest) Most modern desktop environments include a built-in option for this remapping. GNOME (40+): Open Settings → Keyboard → Special Character Options Toggle “Make Caps…
GNOME’s default Alt-Tab behavior switches between applications, grouping all windows from the same app together. If you work with multiple windows in a single application—multiple browser tabs, text editors, or terminals—this becomes frustrating. Here’s how to change it to window-based switching. Using the Alternate Tab Extension The simplest approach is enabling GNOME’s built-in Alternate Tab…
If you want Emacs to run in the terminal without opening an X window, you have several practical options depending on your setup and workflow. Option 1: Install emacs-nox (Recommended for servers) The cleanest approach is installing the no-X variant of Emacs, which is built without X11 support. This reduces memory overhead and startup time…
When you need to identify which package installed a command on your Fedora system, you have several reliable methods depending on whether the package is already installed. Quick lookup for installed commands The fastest approach combines which to locate the command with rpm to query the owning package: $ rpm -qf $(which ping) iputils-8.40-4.fc40.x86_64 The…
The most reliable one-liner to count files in the current directory is: find . -maxdepth 1 -type f | wc -l This counts only regular files (not directories or symlinks) and handles edge cases that trip up simpler approaches. Why Not Use ls | wc -l? The common ls | wc -l command has several…
When you need to download large files faster, parallelizing across multiple connections can significantly improve throughput. Standard tools like wget and curl use single connections by default, but several alternatives support multi-connection downloads that can achieve 3-5x speedups on capable networks. aria2c aria2 is the most powerful option. It handles HTTP, HTTPS, FTP, BitTorrent, and…
Exit codes are how programs communicate success or failure to the shell and parent processes. Understanding them is essential for writing reliable scripts and debugging applications. Linux and Windows handle these differently, so knowing both conventions matters if you work across platforms. Linux Exit Codes On Linux, the convention is simple: 0 means success, 1–255…
The lp command is the standard tool for printing from the Linux command line. It interfaces with CUPS (Common Unix Printing System), the printing backbone on virtually all modern Linux distributions. Basic Printing Send a file to your default printer: lp text-file.txt Specify a particular printer: lp -d printer-name text-file.txt List available printers and identify…
Bash doesn’t have a goto statement, and that’s intentional. The language is designed to encourage cleaner control flow patterns that are easier to debug and maintain. When you feel the urge to jump around in your script, there’s almost always a better approach. Functions and Early Return The cleanest pattern is extracting logic into functions…
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 you run crontab -e, git commit, visudo, or similar commands, Linux applications need to know which text editor to launch. This is controlled by environment variables and system configuration, with several methods available depending on your needs. Understanding EDITOR and VISUAL The EDITOR environment variable tells applications which text editor to use. A related…
When you have shared Makefiles included across multiple projects in different directory structures, relative includes break. If common.mk tries to include release.mk and both files are in a subdirectory like external/, the include fails because Make uses the current working directory, not the location of the including file. For example, this structure works fine: Makefile…
GNOME Shell’s appearance, including the panel, notifications, and system UI, is controlled by CSS theme files. Font customization requires editing these theme files directly. System-Wide Font Changes The primary theme file for GNOME Shell is located at: /usr/share/gnome-shell/theme/gnome-shell.css To modify fonts, open this file with elevated privileges: sudo nano /usr/share/gnome-shell/theme/gnome-shell.css Search for font-family declarations throughout…
GNOME 3 removed the GUI option for customizing window title fonts that existed in earlier versions. The setting is still configurable, but you’ll need to access it through command-line tools or configuration editors. Using gsettings (Command Line) The simplest approach is gsettings, which directly modifies the configuration: gsettings set org.gnome.desktop.wm.preferences titlebar-font ‘Sans Bold 10’ To…
Running your own Python installation on Dreamhost (or similar shared hosting) gives you control over the version, packages, and dependencies without relying on system-wide Python. This is especially useful when you need specific Python versions or packages the hosting provider doesn’t support. Why Use a Custom Python Installation Shared hosting environments typically ship with outdated…
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…
Vim’s default OCaml indentation is limited and doesn’t handle the language’s syntax well. You’ll want to use ocp-indent, a dedicated indentation tool built specifically for OCaml that understands the language’s scoping and structure rules. Installing ocp-indent First, install the tool via OPAM (OCaml Package Manager): opam install ocp-indent If you don’t have OPAM installed, install…
When you need to execute a system command and capture its output in C, popen() is the standard approach. Unlike system(), which just runs a command, popen() gives you a file stream connected to the command’s stdout or stdin. Basic Usage The popen() function signature is: FILE *popen(const char *command, const char *type); The type…
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…