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To see the current file path immediately, use the Elisp evaluation prompt: M-: buffer-file-name This displays the full path in the echo area. Alternatively, press M-x, type eval-expression, and enter buffer-file-name. In Elisp code Reference buffer-file-name directly in your configuration or custom commands: (message “Editing: %s” buffer-file-name) This prints to the echo area and logs…
Bash provides comparison operators for conditionals through the test command (aliased as [), the [[ ]] compound command, and the (( )) arithmetic command. Each has specific use cases and behavior differences worth understanding. String Comparisons String comparisons work with test/[ and [[ ]]: Operator Meaning -n STRING String length is nonzero (true if not…
When debugging a program or understanding what it actually touches on your filesystem, you need to see which files it opens. Two tools do this well: strace traces system calls in real time, while lsof inspects a running process without the overhead. Using strace to capture file operations The simplest approach is to run strace…
DVI (Device Independent) files are the output format from TeX and LaTeX compilers. While modern workflows typically generate PDF directly with pdflatex, you’ll still encounter DVI files in legacy documents, archived projects, and specific publishing pipelines that require intermediate processing. Viewing DVI Files Xdvi Xdvi is the most reliable dedicated DVI viewer and remains the…
When you install a JDK on Linux, you need to configure environment variables so your shell uses the correct Java binary and build tools can locate the installation. If you have multiple Java versions installed, proper configuration becomes essential. Why Set Java Environment Variables Setting JAVA_HOME and PATH ensures: Tools and applications can locate the…
MPlayer is largely obsolete, but if you’re maintaining legacy systems, you’ll need to know how to position windows. For new work, use mpv (MPlayer’s maintained fork) instead. Centering with MPlayer Add this to ~/.mplayer/config: geometry=50%:50% This centers the window by setting both X and Y to 50% of screen dimensions. Override at runtime: mplayer -geometry…
SSH is fast enough for most tasks, but when you’re transferring large files, running multiple commands, or managing hundreds of servers, every millisecond counts. Here’s how to squeeze real performance gains from SSH and SCP on Linux. Choose the Right Cipher Cipher selection has the biggest impact on throughput. Modern CPUs have AES-NI hardware acceleration,…
The Windows (Super) key can be remapped to function as an additional Ctrl key, useful if you work across multiple systems or prefer the extra modifier. The approach varies significantly by display server and desktop environment. GNOME (Wayland and X11) GNOME 3.38 and later have built-in remapping through Settings: Open Settings → Keyboard → Special…
Remapping modifier keys on Linux makes sense if you’re an Emacs power user, prefer ergonomic hand positioning, or simply don’t use the Win key. The standard approach moves frequently-used modifiers closer to your thumbs by trading the underutilized Super/Win key for additional Ctrl or Alt access. A typical remapped layout looks like: |Ctrl|Alt|Ctrl| Space Bar…
When you’ve modified your keyboard layout or key bindings using xmodmap and need to revert to the default, setxkbmap is your primary tool. However, the approach depends on whether you’re running X11 or Wayland, and what aspects of the configuration you want to reset. Check Your Session Type Before attempting any resets, verify whether you’re…
The split command is the standard tool for breaking large text files into smaller chunks on Linux. Here’s the basic syntax: split -l 1024 content.txt splitted-content.txt- This creates output files named splitted-content.txt-aa, splitted-content.txt-ab, and so on, with each containing 1024 lines. Understanding output naming By default, split appends two-character suffixes starting with aa. The naming…
Remapping space to Ctrl while preserving space on tap is useful for modal editors and power users. The challenge: distinguish between a held key (Ctrl) and a quick tap (space). Kernel-level remapping can’t do this, so you need userspace solutions. Quick Comparison of Methods Tool Best For Pros Cons keyd Simplicity, both X11 and Wayland…
Emacs makes heavy use of Ctrl, and many users find it ergonomically difficult to hit Ctrl repeatedly, especially on modern keyboards where Ctrl is placed far from home row. Swapping Alt and Ctrl can make Emacs navigation more comfortable. This guide covers modern approaches for different desktop environments and input systems. Emacs-Only Configuration (Simplest) If…
Memory leak detection is critical for C program reliability. Several tools work at different stages of development—compile time, runtime, and production scenarios. Your choice depends on performance tolerance, integration needs, and how much detail you require. AddressSanitizer (ASan) AddressSanitizer is the first tool to reach for in 2026. It’s compiler-integrated, fast, and catches a broader…
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…
When network interfaces fail or behave unexpectedly, you need to inspect driver details, hardware state, and kernel messages. Here’s the practical toolkit for diagnosing network hardware and driver issues. Kernel Messages and Logs Start by checking kernel logs where driver initialization and errors are recorded: dmesg | grep -i network dmesg | grep -i driver…
When your HP printer runs out of paper mid-job on Linux, the print queue pauses and won’t resume automatically once you reload paper. You need to either clear the error state physically or use CUPS commands to resume printing. Physical Reset Method The quickest approach for most HP printers is to trigger the paper-detect sensor:…
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…