The Unix epoch (January 1, 1970 00:00:00 UTC) is the standard reference point for timestamps across Linux systems. When you need to convert a timestamp like 1349361711.169942 into a readable date, the date command is your primary tool. Basic Conversion The simplest approach uses date with the @ prefix: date -d @1349361711.169942 Output: Thu Oct…
By default, ibus isn’t automatically started on Fedora with Cinnamon. You might try launching the daemon manually: ibus-daemon This starts the ibus service and adds an icon to your system tray, but you’ll find that Chinese input doesn’t work even when enabled through the tray icon. The missing piece is integration with Cinnamon’s input method…
Cinnamon is a modern, feature-rich desktop environment forked from GNOME. It’s lightweight compared to full GNOME installations and offers a traditional taskbar-based interface. Installing it on Fedora is straightforward. Basic Installation Use dnf (the modern package manager) with group install: sudo dnf groupinstall ‘Cinnamon Desktop’ This installs the complete Cinnamon desktop environment along with necessary…
You sometimes need to know whether your shell is running inside screen or tmux. The most straightforward approach is checking the TERM environment variable. Using TERM When screen starts a shell, it sets TERM=screen by default: [user@host ~]$ echo $TERM screen Compare this to a normal terminal session: [user@host ~]$ echo $TERM xterm-256color The TERM…
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….
Counting page views isn’t as simple as incrementing a counter. You need to handle edge cases: duplicate views from the same user, multiple users behind a single IP (corporate networks), and bots. Here’s how to build a robust system. The Problem with IP-Based Counting Relying on IP addresses fails in several scenarios: Multiple users behind…
When you need to store form submissions where different form types have different attributes, you’re essentially implementing an Entity-Attribute-Value (EAV) model. This is a common pattern for flexible schemas, but it requires careful design. The Core Problem You have multiple form types (Laptop, Mobile, Tablet) with different fields. A naive approach is a wide table…
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,…
Amazon’s Kindle Library web interface forces you to delete books one at a time through the UI. If you’ve accumulated hundreds of items, this becomes tedious. Here are practical approaches to bulk-delete from your Kindle Library. Browser Console Method The most straightforward approach uses your browser’s developer console to run deletion scripts directly against Amazon’s…
Java Runtime Environment (JRE) is required to run Java applications on Linux. On x86-64 systems, you have several installation options ranging from open-source to Oracle’s commercial builds. Install OpenJDK (Recommended) OpenJDK is the open-source implementation and is available in all major Linux distributions: # Fedora / RHEL / Rocky Linux sudo dnf install java-17-openjdk #…
Start by compiling your C source files into object files: gcc -c lib1.c lib2.c This produces lib1.o and lib2.o. You can use any compiler flags here—-Wall, -O2, -fPIC, etc.—that match your build requirements. Position-independent code (-fPIC) isn’t strictly required for static libraries but is good practice if you anticipate reusing these objects elsewhere. Creating the…
Working with environment variables in C is straightforward using POSIX APIs. The two primary functions are getenv() for retrieval and setenv() for modification. Getting Environment Variables Use getenv() to read an environment variable: #include <stdlib.h> #include <stdio.h> int main(void) { const char *path = getenv(“PATH”); if (path != NULL) { printf(“PATH: %s\n”, path); } else…
[md] 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:/usr/bin:/bin setenv EDITOR vim setenv JAVA_HOME /usr/lib/jvm/java-17-openjdk…
Setting environment variables in Bash is one of the most fundamental skills for working with Linux command lines and shell scripts. Bash provides several ways to define and manage variables. Setting a Variable for the Current Shell MY_VAR=”hello world” Important: No spaces around the = sign. MY_VAR = “value” will produce an error because Bash…
iOS 7 redesigned the Calendar app with a new interface, and finding the list view (a chronological list of all events) isn’t immediately obvious. Here’s how to access it and make the most of the Calendar app. Access List View in iOS 7 Open the Calendar app Tap the list icon (three horizontal lines with…
C++ provides the <iomanip> header for controlling how data appears when printed to standard output. These manipulators give you precise control over formatting, alignment, precision, and radix. Basic Manipulators The most common manipulators are persistent (they remain active until changed) or stateless (they apply once and reset). Width and Alignment: #include <iostream> #include <iomanip> int…
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…
Designated initializers for aggregate types with non-trivial members (like std::vector) have inconsistent support across GCC versions. This error typically appears when you try to initialize a struct containing standard library containers using designated initializer syntax in the wrong order. The Problem When you compile this code with older GCC versions: struct Stat { vector<int> vec;…
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….
The #trace directive in OCaml’s interactive toplevel (ocaml or utop) logs function calls and returns, showing you exactly what arguments go in and what values come back out. This is invaluable for debugging recursive functions and understanding execution flow. Basic Usage Define a function and enable tracing with #trace: # let rec factorial n =…