just read it

Pipes--->                  it is used to transfer data between two processes in FIFO manner. one processes can transfer data without knowing the what other process is doing in other end. Pipes are used in file system for data storage There are two type named  unnamed Syntax for pipe system call pipe(fdptr) fdptr is the pointer to an integer array that will contain two file discriptor  one is for reading and other is for writing kernel assign the inode for pipe from file system designated pipe device using algorithm "ialloc" unnamed pipe who | wc---->internally shell create unnamed pipe can be used for related processes pipe() syscall   named pipe special file(p) --->mkfifo mkfifo cmd ------->mkfifo syscall can be used for non related processes {if(fork()>0) sleep(1000)} it create zombie process Number of times hello printed is equal to number of proces...

things which make thing easy Ex. creating table in mysql CREATE TABLE student( student_id INT, name VARCHAR(20) NOT NULL, subject VARCHAR(20) /////DEFAULT 'undefined'///UNIQUE/////AUTO INCREMENT, PRIMARY KEY(student_id)///important to mention ); /////inserting data///// SELECT * from student; INSERT INTO student VALUES(1,'rahul','math'); INSERT INTO student VALUES(2,'aaditya','English'); INSERT INTO student VALUES(3,NULL,'biology');//error --->name should not be null INSERT INTO student(student_id,name) VALUES(4,'rajesh');--->for specific use '*' this symbol is used to select all the data from database Ex. select * from student; for specific use  Ex. select major, name from student order by name/////name desc;////asc (ascending) not equal---->     '< >' Projection is unary operator it is used to list it returns arguments which are specific to it • It yields a v...

Android Development - android SDK - language: Java, Kotlin - url: developer.android.com - SDK   - software development kit   - features     - collection of header files or namespaces or packages: packages     - collection of libraries     - toolchain       - compiler or interpreter: javac, dx       - assembler : -       - disassembler : java -p       - linker : -       - debugger : jdb       - extra tools : adb, monkeyrunner, gradle     - documentation : developer.android.com     -----------------------------------------------------------------------------     - Integrate Development Environment: Android Studio     - Emulator or Simulator or VM   : emulator       - qemu: quick emulator       - Genny motion: commercial       - BlueSt...

#Computer fundamentals - cabinet   - power supply (SMPS)   - mother board      - cpu slot(s)       - cpu         - PGA (Pin Grid Array)         - BGA (Ball Grid Array)       - Family         - CISC           - Intel (Integrated Electronics)           - AMD (Advanced Micro Devices)         - RISC           - ARM             - Samsung             - Qualcomm             - Apple             - Motorola ...

egrep [^ letter] ^ means af ter that letter all lines are highlighted egrep[ letter $] $ means before that letter all lines are highlighted egrep[^letter$] inbetween letters are high lightedr -p stands for parent directory it will create folder in home elpthat set if u not use  -p it will not create folder at home by default rm is used to delete only files not whole folder rm -rf is used to remove directory recursively without  asking permission

* Networking - basics   - units     - B: bytes     - b: bits   - IEEE standard: 802     - 802.3: ethernet     - 802.3u: fast ethernet     - 802.11: WiFi     - 802.15: BlueTooth   - definition     - collection/group of devices (mobiles/machines/kitchen application)     - to exchange/share the information   - topology     - physical arrangement of machines     - types       - bus       - ring       - connected ring       - star       - mesh   - types     - wired       - medium: wire/cable       - cables         - co-axial         - category cable (cat cable) (Twisted pairs)           - types             - UTP: Unshielded Twisted P...