The simplest approach is to select text and run untabify: M-x untabify This replaces all tabs in the selected region with spaces, preserving column alignment. If no region is active, Emacs prompts you to define one. Convert the Entire Buffer Select all content, then run untabify: C-x h M-x untabify C-x h selects the whole…
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…
The sort command’s -n flag only handles decimal numbers. When you apply it to hexadecimal values, it falls back to lexicographic (alphabetical) sorting, which produces incorrect results since hex digits don’t follow numeric order alphabetically. Given a file with hex addresses: 400000000 __crt0 400000039 __newr0 400001B14 get_my_task_id 200000020 reg1 20400001000 status Running sort -n will…
When you have multiple consecutive citations like [14], [15], [16], [17], [19], LaTeX renders them individually by default, wasting space. Citation management packages automatically compress these to [14–17], [19], which is standard practice for numerical citation styles. Using the cite Package The cite package is the simplest approach. Add it to your preamble: \usepackage{cite} When…
Chrome aggressively caches HTTP redirects—especially 301 (permanent) and 308 redirects—as a performance optimization. The cache persists across browser sessions, which causes real problems when you’ve updated redirect rules and need to test them immediately. Understanding Chrome’s Redirect Cache Behavior Chrome stores redirect information at the browser level, separate from typical page caches. This means: 301…
GDM (GNOME Display Manager) lets you control which users appear on the login screen. You have two main options: hide the entire user list or exclude specific users while keeping the list visible for others. Disable the user list entirely The most straightforward approach is to disable user listing completely. This forces everyone to type…
The simplest way to see your commit history as a tree structure: git log –graph –oneline This produces a text-based graph showing branch relationships and merges with abbreviated commit hashes: * b5dc8b9 Merge branch ‘main’ into develop |\ | * 7514ef1 revised the README.md | * 6692428 align size to page for both shalloc and…
WordPress sanitizes HTML in comments by default for security. The <pre> tag is stripped unless you explicitly whitelist it. Here’s how to enable it without compromising security. Using wp_allowed_post_html Filter The proper approach is to whitelist <pre> and related tags via the wp_allowed_post_html filter: function allow_pre_in_comments( $allowed ) { $allowed[‘pre’] = array(); $allowed[‘code’] = array(…
You can fetch a webpage as if you’re requesting from a mobile device by setting curl’s User-Agent header to match a mobile browser. Remote servers use the User-Agent header to decide whether to serve mobile or desktop versions of pages. Basic syntax Use the -A (or –user-agent) flag to specify a mobile User-Agent string: curl…
By default, crond sends email notifications whenever a cron job produces output or encounters an error. For high-volume cron jobs or systems without a mail server, you’ll want to disable these notifications. Redirect output to /dev/null The simplest approach is to discard all output from your job: 0 2 * * * /usr/local/bin/backup.sh > /dev/null…
Aggregating multiple RSS feeds into a single source is essential for monitoring diverse content — whether tracking news, blogs, project updates, or monitoring systems. Here are the practical approaches with working examples for 2026. Self-Hosted Feed Readers Miniflux is the modern standard for self-hosted feed aggregation. Written in Go, it’s lightweight, actively maintained, and provides…
The built-in etags command doesn’t recursively traverse directories by default, but generating TAGS files across your entire project is straightforward with the right tools and setup. Using ctags (Recommended) The simplest approach is ctags with the -e flag, which generates Emacs-compatible TAGS files: ctags -e -R . The -R flag enables recursive traversal. This works…
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…
IEEE requires a specific format for web citations, and BibTeX handles this cleanly with the @online entry type. Here’s how to get it right. IEEE Web Citation Format IEEE specifies this pattern for online sources: [#] Initial(s). Surname, “Title [Online]. Available: URL. Accessed: Month Day, Year.” A complete example looks like: [1] J. Jones, “Networks…
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…
The replication factor determines how many copies of each data block HDFS maintains across your cluster. The default is 3, which provides adequate fault tolerance for most deployments by surviving both node and rack failures simultaneously. Setting Cluster-Wide Default Replication To set the default replication factor for all new files, add the dfs.replication property to…
Amazon S3 has a maximum object size of 5TB per object. This limit applies uniformly across all storage classes and regions — there are no exceptions or workarounds. Understanding the 5TB Ceiling The 5TB limit is a hard constraint at the API level. You cannot upload, copy, or restore an object larger than this. While…
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…