When a Bash script spawns child processes—say script A starts B, which starts C, which runs rsync—you need a way to terminate the entire process tree cleanly. Simply killing the parent leaves orphaned children running in the background. The most reliable approach uses session IDs (SID). By default, child processes inherit the same session ID…
The usermod command is the standard tool for modifying user accounts. To change a username, use the -l (or –login) option: sudo usermod -l user1 u1 This changes the login name from u1 to user1. However, there’s an important caveat: usermod only updates the /etc/passwd file. The user’s home directory, mail spool, and other resources…
The free command—along with ps, top, kill, pgrep, and dozens of other system utilities—is maintained as part of the procps-ng project. Source repository The source code is hosted at: https://gitlab.com/procps-ng/procps You can clone it with: git clone https://gitlab.com/procps-ng/procps.git cd procps Most distributions package procps-ng, so you likely already have it installed. You can verify the…
Chrome on Linux sometimes fails to start with the error “Your profile could not be opened correctly.” This typically happens when the browser’s profile database becomes corrupted, often after a crash or unclean shutdown. Quick Fix: Remove Corrupted Web Data The most reliable solution is to delete the corrupted Web Data file from your Chrome…
When managing a Linux system remotely, you sometimes need to terminate all sessions for a specific user—whether they’re logged in locally at the console, via SSH, through X11 forwarding, VNC, or any other method. Here’s how to do it. Quick Answer To terminate all processes for a user named bob: killall -u bob This kills…
As nodes are added or removed from a Hadoop cluster, storage utilization becomes uneven across DataNodes. Some fill up while others remain mostly empty, leading to inefficient resource use and potential storage bottlenecks. HDFS provides the Balancer tool to redistribute blocks across DataNodes and even out disk usage. Understanding the Balancer The HDFS Balancer is…
When a process receives a signal from kill or pkill, it needs a signal handler to intercept and respond to it. Without one, most signals terminate the process immediately. This guide covers setting up robust signal handlers for production daemons. Understanding Signals The kill command sends signals to processes. By default, it sends SIGTERM (signal…
IBus daemon restarts aren’t always straightforward in GNOME, especially since menu options have been removed. You’ll need to kill the daemon and start a fresh one. Quick restart Kill the current IBus daemon: pkill -o ibus-daemon The -o flag terminates only the oldest process, which is typically the main daemon (not child processes). IBus usually…
GNOME Keyring stores encrypted credentials, SSH keys, and secrets for applications. If you need to disable it or start fresh after forgetting the password, you can remove the keyring database. Keyring Storage Locations The location of keyrings depends on your GNOME version and configuration: GNOME 3.0+: ~/.local/share/gnome-keyring/ or ~/.local/share/evolution/calendar/ Older GNOME: ~/.gnome2/keyrings/ XDG Base Directory…
X11 forwarding over SSH lets you run graphical applications on remote systems and display them locally. Firefox is a common use case, though it requires careful configuration to avoid crashes and permission issues. Basic Setup The simplest approach uses X11 forwarding: ssh -X remotehost The -X flag enables trusted X11 forwarding. For untrusted forwarding (more…
Dropbox on Linux has two main approaches: the official daemon (headless) or the sync client with GUI. Which you choose depends on your use case. Official Dropbox Daemon (Recommended for Servers) The daemon is lightweight and works well on headless systems. Download and extract it: cd ~ && wget -O – “https://www.dropbox.com/download?plat=lnx.x86_64” | tar xzf…
Sharing internet from a Windows PC to an iPhone via USB is possible but requires careful network configuration. This is less common than tethering the other direction, but useful when you need a stable wired connection without draining your phone’s battery. Prerequisites Windows 10 or Windows 11 iPhone with iOS 12 or later USB-A to…
Programs need to shut down gracefully—saving state, closing connections, flushing buffers—rather than terminating abruptly. A daemon might receive a termination signal and need to persist in-memory data before exiting. The challenge is catching these signals in C and responding appropriately. Signal basics The kill command sends SIGTERM by default. This signal is catchable and allows…
Emacs startup is slow. If you’re using it for quick edits alongside other tools, waiting 2-3 seconds every time becomes friction. Heavy mode configurations, lazy loading chains, and initialization hooks add up fast. The server/client architecture solves this: start an Emacs server once, then spawn lightweight clients that connect almost instantly. Your first edit waits…
Google stopped updating the PageRank toolbar in 2016 and fully deprecated the public metric by 2024. If you’re still thinking about PageRank as a ranking factor, you’re optimizing for something that hasn’t mattered in over a decade. The PageRank Story PageRank was Google’s original link-based ranking signal — a score from 0-10 displayed in the…
Moving a domain requires more than DNS changes. If you have existing traffic, backlinks, or search engine indexing pointing to your old domain, a proper 301 redirect ensures users and search engines find your content at the new location while preserving SEO rankings. Why 301 Redirects Matter A 301 (“Moved Permanently”) response tells browsers and…
pgrep and pkill are essential tools for finding and signaling processes by name and attributes. They’re far more precise than grepping ps output and should be your go-to for process management scripts and one-liners. pgrep: Find Process IDs pgrep searches running processes and outputs matching PIDs. All selection criteria must match unless you use alternatives…
A SOCKS5 proxy tunneled through SSH provides encrypted communication between your client and a remote server. This is useful for bypassing network restrictions, securing connections on untrusted networks, or routing traffic through a trusted server. Basic Setup The simplest approach uses SSH’s dynamic port forwarding with the -D flag: ssh -D 8080 username@sshd_server This creates…