In this topic we will discuss the most important parts of the Linux OS. In this blog we see detail about Linux Shell and Kernel.
What is the Shell:
The Shell is “Sleeping Beauty of Linux Operating System”. It interacts directly with users. Shell takes text command from the users, carry them out one at a time and returns the result via the output.
The Shell begin to operate as soon as user login to the system. The command from users can’t be understand by the kernel. Shell take roll of interpreter to translate them.
Types of Shell:
1.Bourn shell:- This shell is founded by ‘Stephen Bourne’. It is denoted by ‘sh’.
Command full-path is- /bin/sh and/ sbin/sh
Non-root user default prompt is- $
Root user default prompt is- #
2.Bash Shell:- It is the super shell of bourn shell developed by GNU. It is denoted by ‘bash’.
- Command full-path is- /bin/bash
- Non-root user default prompt is- bash -g.gg$
- Root user default prompt is- bash -g.gg#
3. C-Shell:- This shell created by ‘Bill Joy’ to improve the feature of Bourn shell. Denoted by ‘csh’. It include helpful programming features like arithmetic and c- like expression.
- Command full-path is- /bin/csh
- Non-root user default prompt is- hostname %
- Root user default prompt is- hostname#
4. Korn shell:- David Korn develop the korn shell. It is combination of the c-shell and bourn shell. Denoted by ‘ksh’.
- Command full-path is- /bin/ksh
- Non-root user default prompt is- $
- Root user default prompt is- #
What is the Kernel:
Kernel is the Heart of the Linux system. Its is directly communicate with hardware. It is stay is memory while the system is running all the function.
Service Provide by kernel:
- Process Management:- This model take care of creation and deletion of process. It scheduling resources of two different process.
- Memory Management:- Memory management model take care of memory allocation and de-allocation. It provide memory space to the resources.
- File Management:- It take care of activities such as organization, naming, storage, sharing and protection of files.
- Security:- Security model protect the resources and information of a computer system against unauthorized access and destruction.
Relation Between Linux Shell and Kernel:
- User can communicate with the kernel throw shell.
- Shell starts running when user logon and wait for the input. When user enter the command shell analyze the command.
- When system is boating kernel manage the system memory scheduling resources and process decide their priorities and give the control to shell.