Summary of C Under Linux in C programming language

(a) Linux is a free OS whose kernel was built by Linus Trovalds and friends.

(b) A Linux distribution consists of the kernel with source code along with a large collection of applications, libraries, scripts, etc.

(c) C programs under Linux can be compiled using the popular gcc compiler.

(d)  Basic scheduling unit in Linux is a ‘Process’. Processes are scheduled by a special program called ‘Scheduler’.

(e) fork( ) library function can be used to create child processes.

(f) Init process is the father of all processes.

(g)execl( ) library function is used to execute another program from within a running program,.

(h) execl( ) function overwrites the image (code and data) of the calling process.

(i) execl( ) and fork( ) usually go hand in hand.

(j) ps command can be used to get a list of all processes.

(k) kill command can be used to terminate a process.

(l) A ‘Zombie’ is a child process that has terminated but its parent is running and has not called a function to get the exit code of the child process.

(m) An ‘Orphan’ is a child process whose parent has terminated.

(n) Orphaned processes are adopted by init process automatically.

(o) A parent process can avoid creation of a Zombie and Orphan processes using waitpid( ) function.