Lynxbee topic
This warning usually means the machine’s active hostname no longer resolves through its configured Name Service Switch sources. Diagnose the exact name first, correct `/etc/hosts` or hostname configuration safely, and verify through `getent` before changing DNS.
Installing the old `skypeforlinux` package is no longer a working solution: Microsoft retired Skype on May 5, 2025. Ubuntu users should move to Teams on the web or its PWA, handle any remaining Skype data, and remove the unsupported client.
Linux procfs exposes a live, file-like view of process state without creating ordinary files on disk. This lab starts a harmless C process, captures its PID, inspects the useful `/proc/PID` entries, and cleans up reliably.
Monitor mode, or RFMON (Radio Frequency MONitor) mode, allows a computer with a wireless network interface controller (WNIC) to monitor all traffic received from the wireless network. Monitor mode allows packets to be captured without having to associate with an access point or ad hoc network first.
Write a C packet sniffer in Linux using AF_PACKET raw sockets to capture, decode, and analyze Ethernet, IP, TCP, and UDP frames on wlan0.
Write a C program in Linux using inotify_init and inotify_add_watch to monitor directory file creation, modification, and deletion events in real time.
Program Linux framebuffer devices (/dev/fb0) in C: query screen resolution via ioctl, map video memory with mmap, and render raw RGB pixel buffers.
Write a C program in Linux to parse Windows BMP image headers, convert 24-bit BGR pixels into raw 16-bit RGB565 binary data for embedded LCD displays.
Learn how to manually trigger the Linux Kernel Out-Of-Memory (OOM) killer via SysRq, inspect /proc/pid/oom_score, and protect critical processes.
Turn your Linux PC or Raspberry Pi into a wireless Bluetooth speaker for smartphones using BlueZ, PipeWire, and PulseAudio A2DP audio routing.
Configure Ubuntu Linux as a Bluetooth A2DP Sink audio receiver to stream audio wirelessly from mobile phones using PulseAudio, PipeWire, and BlueZ.
Fix Chrome error 'Something went wrong when opening your profile' on Linux by removing SQLite lock files, fixing permissions, and restoring data.
Resolve 'no permissions (user in plugdev group; are your udev rules wrong?)' error on Linux by configuring /etc/udev/rules.d/51-android.rules.
Scan and list available Wi-Fi networks in Linux using nmcli, iw, and iwlist. Learn BSSID, SSID, RSSI signal strength, and channel parsing.
Resolve 'error: package android.support.v7.app does not exist' and 'cannot resolve symbol AppCompatActivity' by migrating to AndroidX in Gradle.
Automate RSS 2.0 XML feed generation from website URLs using Bash, curl, date RFC-822 formatting, and XML entity escaping.
Master Java UDP socket programming: complete client-server code using DatagramSocket and DatagramPacket, packet buffering, and MTU mechanics.
Understand Linux terminal file color codes: reference color tables for directories, symlinks, SUID, and customize LS_COLORS using dircolors.