If you’ve forgotten your iPhone passcode, you’ll need to erase the device and set it up again. Apple provides several official methods, but recovery mode is the most straightforward and reliable approach for most users. Before You Start Recovery mode will completely erase your iPhone. Make sure you have a backup if possible, though if…
[md] Systemd’s coredump handler captures process crash dumps by default, which can consume significant disk space on development or test systems. Here’s how to disable or control coredump storage. ## Quick Solution Edit /etc/systemd/coredump.conf and set: [Coredump] Storage=none Then reload the systemd daemon: systemctl daemon-reload This prevents coredumps from being stored permanently while still logging…
When you export a variable in Bash, it becomes available to all child processes spawned from your shell. Sometimes you need to remove that exported status or delete the variable entirely. There are two main approaches depending on what you want to achieve. Remove export status but keep the variable If you want the variable…
When writing C programs on Linux that handle file paths, you need to allocate buffers safely. The kernel defines maximum path and filename lengths through standard macros in <linux/limits.h>. Getting the limits On Linux systems, <linux/limits.h> provides two key macros: NAME_MAX — maximum length of a single filename component (255 characters) PATH_MAX — maximum length…
When you have an absolute path like /foo/bar/baz.txt and need to split it into its components, Bash provides two essential utilities: dirname and basename. Using dirname and basename The dirname command returns the directory portion of a path, while basename returns just the filename: p=”/foo/bar/baz.txt” dirname “$p” # Output: /foo/bar basename “$p” # Output: baz.txt…
When you try to redirect output from a sudo command to a file using >, you’ll hit a permission error: $ sudo echo “echo hello” > /usr/local/bin/hello bash: /usr/local/bin/hello: Permission denied This happens because the shell processes the redirection operator > before sudo runs. The redirection happens in your unprivileged shell context, not as root….
GNU Screen is a terminal multiplexer that lets you manage multiple shell sessions within a single window. If you’re new to it, here are the best resources to get up to speed, plus practical tips for getting started. Getting Started with Screen For an introduction to the basics, start with A quick tutorial on screen….
Converting text to lowercase is a common task in shell scripts and command-line workflows. Linux offers multiple approaches, each with different trade-offs in performance, portability, and Unicode handling. Using tr for simple conversions The tr command translates characters and is widely portable across Unix-like systems: echo “HELLO WORLD” | tr ‘[:upper:]’ ‘[:lower:]’ Output: hello world…
When a kernel panic occurs on a remote Linux server, manual intervention via SSH becomes impossible. The kernel can be configured to automatically reboot after a panic, allowing the system to recover without human intervention. Enable Kernel Panic Auto-Reboot The kernel.panic parameter controls this behavior. A value of 0 disables auto-reboot; any positive integer specifies…
Rocky Linux 9 can blank the console screen after a period of inactivity, but by default it may not actually power off the display. This is often caused by kernel mode settings or DPMS (Display Power Management Signaling) configuration. Check Current DPMS Status First, verify whether DPMS is enabled on your console: cat /sys/module/kernel/parameters/consoleblank If…
RPM Fusion provides packages that Fedora and RHEL can’t ship by default due to patent, licensing, or trademark restrictions. This includes multimedia codecs, proprietary drivers, and other software. Here’s how to enable it on RHEL 9 and Rocky Linux. Enable RPM Fusion Free and Non-Free # Enable EPEL first (required dependency) sudo dnf install epel-release…
Fedora’s default repositories don’t include musl libc, but you have two practical options: install it from a community repository if available, or build from source. Building from source gives you full control and is the most reliable approach across Fedora versions. Option 1: Build from Source (Recommended) Start by installing the build dependencies: sudo dnf…
Converting between Simplified Chinese (SC) and Traditional Chinese (TC) characters on Linux is straightforward with OpenCC, a mature open-source tool designed specifically for this task. Installing OpenCC Most distributions include OpenCC in their standard repositories: # Debian/Ubuntu sudo apt install opencc # RHEL/CentOS/Fedora sudo dnf install opencc # Arch sudo pacman -S opencc Alternatively, build…
MPlayer has been largely superseded by mpv in most Linux distributions, but if you need the classic MPlayer with DVD navigation support, building from source remains the way to get libdvdnav integrated. Most distribution packages omit this feature due to licensing complexity. Prerequisites You’ll need a C compiler, build tools, and development libraries. On Fedora/RHEL-based…
musl libc is a lightweight C library implementation that’s useful for creating statically-linked binaries, containerized applications, and embedded systems. It’s the standard C library in Alpine Linux and increasingly common in production environments. Installation from distribution repositories The simplest approach is installing musl from your distribution’s repositories: sudo apt update sudo apt install musl musl-dev…
When you need to audit disk usage or understand directory structure, counting files in each subdirectory is a common task. This is especially useful when dealing with large directory trees where you need a quick overview of distribution. The Basic Approach The simplest method uses a loop with find and wc: for i in */;…
A sequence point is a point in execution where all side effects from previous evaluations are guaranteed to be complete and visible. Understanding sequence points is critical for writing correct C code, especially when dealing with expressions that modify variables. The C standard defines side effects as changes to the state of the execution environment…
When working with codebases that use non-standard file extensions for C source files, ctags won’t recognize them by default. You can configure it to treat files with custom extensions like .c0 or .puc as C source code. Using the langmap option The simplest approach is to add language mappings to your ctags configuration. Edit ~/.ctags…
Vim determines file types by extension to apply syntax highlighting and indentation. If you have custom file extensions that should be treated as C files, you need to configure Vim to recognize them. Using autocommand in .vimrc Add an autocommand to your ~/.vimrc: ” Treat .h and .c files in a custom directory as C…
When you need to share work in progress or maintain a separate feature branch on a remote Git server, you’ll need to create a local branch and push it upstream. Here’s how to do it properly. Basic workflow The fundamental process involves three steps: Create a local branch and switch to it Make changes and…