If you need to remove excess white space or trim margins from PDF files, several graphical tools can handle this on Linux. Here are the most practical options. Krop Krop is a straightforward tool specifically designed for PDF cropping. It lets you define crop regions visually and apply them to single pages or entire documents….
When you start a VNC server with the -geometry flag under GNOME 3, you’ll notice the display resolution doesn’t match what you specified: vncserver -geometry 1024×768 This works fine with GNOME 2 and window managers like twm, but GNOME 3 ignores the setting. The actual resolution will be whatever was last used in that session,…
Note: Java in web browsers is obsolete. Most websites stopped requiring Java applets years ago, and all major browsers removed plugin support by 2016. If you’re here because a legacy application needs Java, consider running it in a containerized environment or dedicated VM instead. If you absolutely must proceed, here’s what you need to know….
The basic syntax for setting an environment variable is: export VARIABLE=value No spaces around the equals sign. If your value contains spaces, quote it: export PATH_TO_PROJECT=”/home/user/my project” Verify it’s set: echo $VARIABLE Viewing all environment variables Use printenv to list all exported variables: printenv Or filter for a specific variable: printenv PATH The env command…
Use setenv to set an environment variable in csh: setenv VARIABLE value Replace VARIABLE with the name of the variable and value with its value. The variable is immediately available in the current shell and inherited by child processes. Examples Set a simple variable: setenv PATH /usr/local/bin:$PATH setenv EDITOR vim setenv JAVA_HOME /usr/lib/jvm/java-17-openjdk Use quotes…
When you need to page through error output from a command, you’ll run into the issue that less only receives stdout by default. Error messages go to stderr (file descriptor 2), so they’ll still scroll past on your terminal while stdout gets paged. Basic approach: combine stderr with stdout make 2>&1 | less The 2>&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….
Accessing Linux filesystems from Windows is useful when dual-booting, migrating data, or recovering files. Read-only access is essential to prevent accidental corruption of ext4 metadata and data. Why Read-Only Access Matters Ext4 is designed for Linux environments. Windows drivers lack complete understanding of ext4 journaling, extended attributes, and other advanced features. Writing through an incomplete…
You can delete cookies from individual sites without clearing your entire browser cache. Here’s how: Via Settings UI Open chrome://settings/privacy in the address bar (or go to Settings > Privacy and security) Click Cookies and other site data Click All cookies and site data Use the search box to find the domain you want to…
There are several reliable methods to generate random strings of a specific length in bash. The choice depends on your character set requirements and use case. Using tr with /dev/urandom The tr command combined with /dev/urandom is the most portable and straightforward approach: tr -dc “[:alpha:]” < /dev/urandom | head -c 10 This produces a…
Cron is a minimal execution environment. Unlike your interactive shell, cron runs with a stripped-down environment containing only a few variables like PATH, MAILTO, and SHELL. Any variables you’ve defined in your shell profile won’t be available unless you explicitly source them in your crontab entries. The Problem If your cron job depends on environment…
Broken links damage SEO, hurt user experience, and undermine site credibility. Checking for them should be part of your regular maintenance routine. Here’s what’s available in 2026. Online Tools W3C Link Checker (http://validator.w3.org/checklink) remains a solid option for checking individual pages. Point it at a URL and it crawls the page’s links, reporting broken ones…
PuTTY stores all SSH session configurations in the Windows registry under HKEY_CURRENT_USER\Software\SimonTatham\PuTTY. This includes hostnames, connection settings, terminal preferences, and authentication keys. Exporting PuTTY settings To back up or migrate your PuTTY profiles to another machine: Open Registry Editor by pressing Win+R and typing regedit Navigate to HKEY_CURRENT_USER\Software\SimonTatham Right-click the SimonTatham folder and select Export…
Attachments in WordPress are tied to specific posts through a parent-child relationship stored in the database. This matters more than you’d think — attachment metadata, URLs, and admin filtering all depend on that parent assignment. Sometimes you need to reassign an image or document to a different post, whether because of organizational restructuring, post merging,…
When you install Core via opam, the interface files (.mli) are stored in your OPAM switch directory. The exact path depends on your OCaml version and OPAM setup. Standard Location The .mli files for Core are located at: ~/.opam/$(OCAML_VERSION)/lib/core/ where $(OCAML_VERSION) is your installed OCaml version. For example, with OCaml 5.2: ~/.opam/5.2.0/lib/core/ Individual modules follow…
Redis is an in-memory data structure store designed for speed and simplicity. Understanding its architecture and consistency guarantees is essential for deploying it correctly in production systems. Core Architecture Redis operates as a single-threaded, event-driven server that uses an in-memory data store with optional persistence. The single-threaded nature simplifies reasoning about concurrent access — all…
Vim’s regex engine is powerful but requires understanding its syntax rules, which differ significantly from standard POSIX extended regex. Whether you’re doing basic substitutions or complex text transformations, knowing how Vim handles regex patterns will save you hours of frustration. Vim Regex Basics Vim supports multiple regex engines, controlled by the magic setting. By default,…
Determining the number of CPU cores available on a Linux system is essential for performance tuning, application configuration, and capacity planning. Several approaches exist depending on what information you need. Quick check: nproc The simplest way to get the number of CPU cores is nproc: $ nproc 8 This reports the number of logical processors…
This error occurs when Fedora’s Anaconda installer cannot properly configure the bootloader, typically when it encounters conflicts between EFI and legacy boot modes or when the partition table format doesn’t match the system firmware expectations. Root Cause The error “you have not created a bootloader stage1 target device” usually indicates one of these issues: UEFI…
To check which storage engine a table uses, query the information_schema database: SELECT ENGINE FROM information_schema.TABLES WHERE TABLE_SCHEMA = ‘database_name’ AND TABLE_NAME = ‘table_name’; Replace database_name and table_name with your actual values. You can also use the SHOW TABLE STATUS command for a quicker view: SHOW TABLE STATUS FROM database_name WHERE Name = ‘table_name’\G The…