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$ ip route show
default via 192.168.1.1 dev eth0 192.168.1.0/24 dev eth0 proto kernel 10.0.0.0/24 via 192.168.1.20 dev eth0
$
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ADB CommandsOpen technology index
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Fastboot Says “No Permissions”? Diagnose USB Before Editing udevADB Commands
Existing libraryA fastboot permission error is fixable, but only after you know Linux can see the bootloader. This diagnostic path separates USB, mode, tool, group, and udev-rule failures without normalizing sudo fastboot.
Who Is Really Logged In to This Linux Machine?Basic Linux Commands
Existing libraryThe who command can settle a tense “is anyone still using this server?” moment—provided you understand what its session records can and cannot prove.
Let the Linux tree Command Explain a DirectoryLinux Commands
Existing libraryTurn an unfamiliar directory into a readable map with tested tree commands for depth, filtering, metadata, symlinks, and machine-readable output.
Find the Right Files on Linux Without Fear of the ResultLinux
Existing libraryBuild predictable Linux find expressions for names, types, sizes, and file contents, then inspect every match safely before taking action.
Safely Rename Parts of Filenames and File ContentLinux
Existing libraryRenaming `memory_map.c` to `memory_mapping.c` and changing identifiers inside source files are separate operations. This guide previews both, handles unusual filenames, refuses collisions, keeps backups, and makes rollback practical.
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Clear filtersField guideOperating System Concepts
01Protect Shared State with pthread_mutex_lock
A POSIX mutex does not make a variable magically private; it gives cooperating threads one serialized critical section and establishes synchronization around protected state. Build a checked C example, understand why the unlocked version is undefined, find races with ThreadSanitizer, and choose between mutexes and atomics.
Field guideC Programs
02Inspect File Attributes in C Using the stat System Call
The stat() system call in POSIX C returns file metadata—including file size, inode number, permission bits, block allocation count, ownership UIDs, and access timestamps—from a file's inode structure without opening or reading the file contents. The struct stat data structure The system header <s
Field guideLinux, OS Concepts and Networking
03Difference between Spinlock and Semaphore
Spinlocks Spinlocks assume the data you are protecting is accessed in both interrupt-handlers and normal kernel code. … Read more
Field guideLinux, OS Concepts and Networking
04Difference between Mutex and Semaphore
Besides the better readability, the code for mutex is smaller and slightly faster than the semaphore implementation. … Read more
Field guideLinux, OS Concepts and Networking
05What is Zombie process and How to create zombie process in Linux
Zombie process is the process which died immediately and whose parent didn’t cared to handled the status … Read more
Field guideLinux Networking
06C program to read mac address using WiFi interface name
If you need to get the mac address of certain wifi interface using C program, you can … Read more
Field guideCore Kernel
07What is Linux Out-Of-Memory OOM Killer
Major distribution kernels set the default value of /proc/sys/vm/overcommit_memory to zero, which means that processes can request … Read more
Field guideCore Kernel
08Avoid a process from being killed in case of Out of Memory
In our previous post, we understood “What is Out of Memory Killer ?” In this post, we … Read more
Field guideLinux Host, Ubuntu, SysAdmin
09Avoid zombie process in Linux
Zombie process is the process which dies/finishes immediately and whose parent didn’t cares to handle the status … Read more
Field guideLinux, OS Concepts and Networking
10Create process in Linux using fork system call
Below is simple process creation program using fork system call, fork return child’s process Id in main/parent … Read more
Field guideLinux, OS Concepts and Networking
11C program to check total and free RAM memory in Linux
Following C program helps you to identify what is the total and free memory / RAM available … Read more
Field guideC Programs
12Example for using shared data between two Unix threads
Following is the simple example to show, how we can create two threads at a time and … Read more
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