Tethering your iPhone to your computer’s internet connection via USB is useful when you need a stable, low-power connection or want to avoid wireless overhead. This guide covers the practical setup on Windows and how to configure your iPhone to use your PC’s internet. Windows USB Tethering Setup On Windows 10/11: Install iTunes or Apple…
The YARN resource scheduler determines how cluster resources are allocated to jobs. By default, Hadoop uses the Capacity Scheduler, but you can switch to an alternative like the Fair Scheduler or configure different scheduling policies. Identifying Your Current Scheduler Check which scheduler is currently active by examining your configuration: grep -A 2 “yarn.resourcemanager.scheduler.class” $HADOOP_HOME/etc/hadoop/yarn-site.xml The…
The usermod command is the standard tool for modifying user accounts. To change a username, use the -l (or –login) option: sudo usermod -l user1 u1 This changes the login name from u1 to user1. However, there’s an important caveat: usermod only updates the /etc/passwd file. The user’s home directory, mail spool, and other resources…
Python provides several ways to check if files or directories exist, with different trade-offs depending on your use case. Using pathlib (recommended) The modern approach uses pathlib.Path, which is cleaner and more object-oriented: from pathlib import Path path = Path(‘/etc/passwd’) # Check if path exists (file or directory) if path.exists(): print(“Path exists”) # Check if…
When running scripts as root, you often need to execute commands with the environment of a different user. The most reliable way to retrieve another user’s PATH is by spawning a login shell under that user’s context. Basic Approach user1path=$(su – user1 -c ‘echo $PATH’) This spawns a login shell (-) as user1 and outputs…
When you try to unmount a filesystem, Linux sometimes refuses with a “device is busy” error. This safety mechanism prevents data loss when processes are actively using the filesystem. But there are legitimate cases where you need to force an unmount: a dead NFS server, a failed USB device, or a hung mount that won’t…
To identify the developers who’ve contributed the most commits to a repository, use git log with some text processing: git log –format=’%aN’ | sort | uniq -c | sort -rn This returns a sorted list with commit counts and author names: 247 Paul Phillips 45 Dale Wijnand 12 Yamashita Yuu 10 Gilles Cornu 8 Josh…
When Linux fails to boot with the error message “sulogin: can not open password database” despite /etc/passwd and /etc/shadow appearing intact, SELinux is often the culprit. The files exist and have correct content, but SELinux context labels are missing or corrupted, preventing the login process from reading them. Diagnose the Problem Boot into the initramfs…
Backing up text messages from Android works best through Google Messages for real-time web access, or via ADB and third-party tools for local archives. Your approach depends on whether you need cloud sync, local storage, or both. Google Messages for Web (Easiest) The simplest method for most users is Google Messages, which syncs SMS and…
When accepting path input in Bash scripts, users might provide /path/to/dir/ or /path/to/dir. Normalizing these to a consistent format without the trailing slash is a common requirement. The Problem You need a reliable method that: Removes trailing slashes if present Works with both files and directories Handles paths that already lack a trailing slash Works…
When you need to access files from a Xen guest’s disk image without booting the VM, you can attach and mount its partitions directly on the host using kpartx. This is useful for recovery, forensics, backup verification, or migrating data between systems. Using kpartx to expose partitions The kpartx utility creates device mappings for partitions…
When you connect an external keyboard to your laptop, accidental key presses from the built-in keyboard can be annoying. Disabling it entirely is straightforward on Linux and can save you from errant inputs while keeping the option to re-enable it when needed. Find Your Keyboard Device Start by listing all input devices to identify your…
The /etc/sysconfig/network-scripts/ directory contains network configuration files on RHEL and Fedora systems. While newer systems increasingly use NetworkManager and systemd-networkd, understanding ifcfg files remains essential for legacy systems and certain enterprise environments. Basic Static IP Configuration Here’s a typical ifcfg-eth0 file for a static IP setup: DEVICE=eth0 TYPE=Ethernet BOOTPROTO=none ONBOOT=yes IPADDR=192.168.1.151 NETMASK=255.255.0.0 GATEWAY=192.168.1.10 USERCTL=no The…
When you need to traverse a directory tree in Python, you have several options. The choice depends on whether you want recursive traversal, how you want to handle the results, and your Python version. Using os.walk() The os.walk() function is the classic approach for recursively iterating through directories. It yields tuples of (dirpath, dirnames, filenames)…
The simplest way to detect whether your Linux system booted in UEFI or BIOS (Legacy) mode is to check for the existence of the EFI firmware directory. Check for EFI Directory The /sys/firmware/efi/ directory only exists when the system has booted in UEFI mode. If it’s absent, the system is running in BIOS/Legacy mode. […
While BIOS settings are the preferred way to disable USB 3.0, you can also force USB 2.0 mode on a running Linux system by manipulating the xHCI controller’s port routing register directly using setpci. How it works Intel xHCI controllers use the XUSB2PR (xHC USB 2.0 Port Routing Register) at offset 0xd0. Setting this register…
Chrome stores passwords encrypted in the system keyring (GNOME Keyring, KWallet, or Pass depending on your desktop environment). To export them in plain text, you’ll need to create a temporary Chrome profile with basic (unencrypted) password storage, sync your passwords from Google Cloud, then extract them from the SQLite database. Prerequisites Chrome or Chromium installed…
Virtual hosts allow you to serve multiple websites from a single Apache server and IP address. This is the standard approach for shared hosting and cost-effective server deployments. Basic Virtual Host Setup The foundation of multi-site hosting on Apache is the VirtualHost directive. Each domain needs its own block that specifies where its files live…
By default, Fedora doesn’t enable SSH access. You’ll need to install OpenSSH server, start the service, and configure your firewall to allow connections. Install OpenSSH Server sudo dnf install openssh-server openssh-clients The openssh-clients package provides the ssh command for connecting to other machines, while openssh-server allows incoming connections. Start and Enable the SSH Service sudo…
OpenWrt runs Dropbear as its SSH server instead of OpenSSH. While Dropbear supports RSA and modern key types, the authorized_keys file lives in a different location, which causes ssh-copy-id to fail silently. Here’s how to set up key-based authentication properly. Why ssh-copy-id doesn’t work ssh-copy-id looks for ~/.ssh/authorized_keys on the remote system, which is OpenSSH’s…