Nishit

 Understood kernel, kernel modules and kernel mode/space. In kernel we have kernel core and kernel modules and majority of our kernel is made of kernel modules. Here instability in any kernel module can take down whole kernel.  

 Today i started working on Beaglebone, loaded the firmware and ssh on debian. Well I wasted a lot of time connecting beaglebone to internet, to do that:      step 1: connect bb via usb cable     step 2: use this command to ssh at bb  ssh debian@192.168.7.2                     ❌ ssh debian@beaglebone.local          ✅                  because when I turn on internet sharing, ip would change.     step 3: run sudo dhclient usb0 or usb1     

 I switched to macOs from Ubuntu and yeah working on it, should think what to write here to show productivity.

Kernel module What: It is a piece of compiled code (like a .ko file) that acts as a plugin. Why: To keep the system efficient and flexible, loading code only when hardware is present, or it would be stored in storage. How: The kernel reads the file, uses the Vendor/Product IDs to match the driver, and performs Dynamic Linking to connect the function calls. When: It happens on demand (e. g., hot-plugging a USB). Where: It runs in Kernel Space , sharing the highest privileges (and risks) with the OS core. Revise C and Embedded C to use for kernel module. 1) check for armstrong numbers.  #include <stdio.h> int length ( int n ) { int len = 0 ; while ( n != 0 ) { n = ( int )( n / 10 ); len ++ ; } return len ; } int number_separator ( int n , int * arr ) { int a = n ; int len = length ( n ); for ( int i = len - 1 ; i >= 0 ; i -- ) { arr [ i ] = ( a % 10 ); a = a ...

 Kernel : It is Resource manager of our system, It starts  

Let's revisit the basics.      

 Start with OS fundamentals today s - Lets know use of folders in root directory bin/sbin - they store system binaries(cat, ls etc) boot - here all OS related files is stored dev - here hardware is behaving as files. etc - It will store system config files home - it is dedicated space for users for install softwares and configurations. lib - This is where libraries are stored, they are essential for programs media - This is where storage disk are located and usb storage are mounted here by default. mnt- This is where the manually attached storages and devices shows up. opt- This is storage to store softwares. proc- Just like dev (devices) it stores processes as files. root-It is directory for root user. run- this is temporary files folder. snap - Snap packages stored here srv - it is a dedicated folder for services such as ftp. sys - It can be used to interact with kernel. tmp - it is temporary directory, usr - It is used to store binaries and libraries for non-essential applicatio...

 Today I found an guide for learning Bash, by guide i meant proper documentation that would help me learn bash scripting in Github. Well I found much better documentation on shell scripting, this is from Apple and this is final documentation I am going to use for shell scripting. day-2 of Advent of code completed.

- Let's start the day by making a script that uses printf and read commands.         using pattern printing for practice from simple 1D patterns to 2D patterns: 1D patterns :     vertical lines     horizontal lines *Don't take spaces lightly during Shell scripting. Today I completed 1st day of AdventOfCode  In first part, I just added and substracted the value because it was simpler compared to part 2. exec 3 < $"day1-input" dial = 50 password = 0 while read -u 3 -r line do if [ "${ line : 0 : 1 }" = "R" ] then echo case of turn right $line dial = $(( dial+(($ {line:1: ${ # line } } )))) #if [ $dial -gt 100 ] ; then ((password++)) ; echo password : $password ; fi dial = $(( $dial % 100)) echo value of dial is $dial if [ $dial -eq 0 ] ; then (( password ++ )) ; echo password : $password ; fi fi if [ "${ line : 0 : 1 }" = "L" ] then echo case of turn lef...

19) grep :  it is used to find pattern/string in files examples:- grep Name sample.txt grep -v Name sample.txt grep -n Name sample.txt grep -c Name sample.txt grep -i name sample.txt grep Name sample1.txt sample2.txt echo grep -i error *.log grep 5 sample.txt grep -v 5 sample.txt grep -r grep ~/Documents grep -ri Error ~/Documents our sample.txt file: MARKSHEET - Class 10A | Roll No | Student Name | Math | English | Science | History | Total | Grade | |---------|--------------|------|---------|---------|---------|-------|-------| |    1    |  Aman Kumar  |  85  |    78   |    88   |   82    |  333  |   A   | |    2    | Priya Sharma |  92  |    85   |    90   |   88    |  355  |   A+  | |    3    | Rahu...

19)grep:-    20) ar :- it is used to create and manage archive(examples of archive are multi module library in python) *Well I can try this for daily codes (/d1/c1,d1/c2,d2/c1) 21) curl :-   A tool to transfer data to or from a server, using any of the supported protocols we can use curl to send email: curl --url [SMTP URL] --mail-from [sender_mail] --mail-rcpt [receiver_mail] -n --ssl-reqd -u {email}:{password} -T [Mail text file] For calling API :  curl -X POST -d "q=22.237481,70.675301&key=value" http://api.weatherapi.com/v1/current.json   For downloading files: curl weather.png cdn.weatherapi.com/weather/64x64/day/116.png To handle authentication -u is used -u <user>:<password> 22)xdg-open :- it simply opens specified file or url. 23) args :  24 ) export : basically we can set path variables in linux and it takes immediate effect.

Here is your blog post, reformatted for better readability. I have consolidated duplicate entries, fixed the numbering, and applied Markdown styling to the code and lists while keeping your original wording and personal notes intact. Asked to learn and understand linux commands (well no idea which or of what category) Well let's go to Geeks, and start understanding linux commands. 1) access hmm, quite useful command, i can put this in bash scripts before working on a file. Syntax: C int access ( const char *pathname, int mode) ; Where: pathname: This argument specifies the path to the file or directory you want to check. mode: This argument specifies the type of access to check for. It can include one or more of the following flags: F_OK flag: Used to check for the existence of a file. R_OK flag: Used to check for read permission bit. W_OK flag: Used to check for write permission bit. X_OK flag: Used to check for execute permission bit. Note: I ran into problems by chec...