Linux Shell. Linux Command-Line Interface. ■ Linux shells: A shell is a command interpreter that allows you to type commands from the keyboard to interact with the operating system kernel.
■ Linux shells: A shell is a command interpreter that allows you to type commands from the keyboard to interact with the operating system kernel.
■ sh (Bourne Shell) The sh shell was the earliest shell, being developed for UNIX back in the late 1970s.
■ bash (Bourne-Again Shell) The bash shell is an improved version of the sh shell and is one of the most popular shells today. It’s the default shell used by most Linux distributions.
■ csh (C Shell) The csh shell was originally developed for BSD UNIX. It uses a syntax that is very similar to C programming.
■ tsch The tsch shell is an improved version of the C Shell. It is the default shell used on FreeBSD systems.
■ zsh (Z Shell) The Z Shell is an improved version of the bash shell.
/ : denote root directory
./ : denote current directory
■ halt This command shuts down the operating system, but can only be run by the root user.
■ reboot This command shuts down and restarts the operating system. It also can only be run by root.
date Sat Aug 31 17:18:53 BST 2002
■ su (switch user) This command switches the current user to a new user account. This command is most frequently used to switch to the superuser root account. In fact, if you don’t supply a username, this utility assumes that you want to change to the root account. If you enter su -, then you will switch to the root user account and have all of root’s environment variables applied.
■ env This command displays the environment variables for the currently logged-in user.
■ echo This command is used to echo a line of text on the screen. It’s frequently
used to display environment variables.
Ex: echo $PATH
■ top This command is a very useful
command that displays a list of all
applications and processes currently
running on the system.
■ which This command is used to display the full path to a shell command or utility.
Ex: which ls
It display: /bin/ls
■ whoami This command displays the username of the currently logged-in user.
■ netstat This command displays the status of the network, including current connections, routing tables, etc.
■ route This command is used to view or manipulate the system’s routing table.
■ ifconfig This command is used to manage network boards installed in the system. It can be used to display or modify your network board configuration parameters.