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System AdministratorResponsible for?
• Install OS • Network Configuration• Security Configuration• Patching• Backup• Performance Management• Storage Management• User Management• TroubleShooting & Maintainance• Vendor Management Created by
• Simply put, the shell is a program that takes your commands from the keyboard and gives them to the operating system to perform. In the old days, it was the only user interface available on a Unix computer. Nowadays, we have graphical user interfaces (GUIs) in addition to command line interfaces (CLIs) such as the shell.
• On most Linux systems a program called bash (which stands for Bourne Again SHell, an enhanced version of the original Bourne shell program, sh, written by Steve Bourne) acts as the shell program. There are several additional shell programs available on a typical Linux system. These include: ksh, tcsh and zsh.
• Bourne Shell (sh) -- This shell does not have the interactive facilities provided by modern shells such as the C shell and Korn shell.
• C Shell (csh) -- It provides a C-like language with which to write shell scripts - hence its name.
• Korn Shell (ksh) -- It provides all the features of the C and TC shells together with a shell programming language similar to that of the original Bourne shell.
• Bash Shell(bash) -- Bash provides all the interactive features of the C shell (csh) and the Korn shell (ksh). Its programming language is compatible with the Bourne shell (sh).
PATH
• Absolute Path:-> An absolute path is defined as the specifying the location of a file or directory from the root directory(/). In other words we can say absolute path is a complete path from start of actual filesystem from / directory. Eg: /var/ftp/pub
• Relative Path:-> Relative path is defined as path related to the present working directory(pwd). Suppose I am located in /var/log and I want to change directory to /var/log/kernel. I can use relative path concept to change directory to kernel .Eg: pwd