Linux-linux Command and Shell

Linux command and Shell

The so-called Shell is the command interpreter, which provides programming interfaces that can be programmed using programs. Learning the shell is very important for Linux beginners to understand Linux systems. LThe shell of the inux system, as the shell of the operating system, provides the user with an interface to use the operating system. The shell is the general term of command Language, command interpreter and programming language, and is the user andinterface programs between Linux kernels. If you think of the Linux kernel as the center of a sphere, the shell is around the outer layer of the kernel. When you pass a command from a shell or other program to Linux
the kernel responds accordingly.

shell in the role of Linux system and MS DOS Command.com and Windows 95/98
explorer.exe similar.

while the shell is not part of the system core, it is only an extension of the system core, but it can invoke most of the functions of the system kernel. Therefore, it can be said thatThe shell is the most important utility for Unux/linux.
There are several types of shells in Linux, the most common of which is BourneShell (SH), C Shell (CSH), and Korn shell (Ksh). The default shell for most Linux distributions is BourneAgain Shell, which is an extension of the Bourne Shell, called Bash, is completely backwards compatible with the Bourne Shell and is BourneThe shell is based on a number of features added. Bash is placed in/bin/bash to provide functions such as command completion, command editing, and command history tables. It also contains a lot of CShell and Kornthe advantages of the shell are flexible and powerful programming interfaces while having a friendly user interface. Of the more than 200 commands in the Linux system, 40 are internal commands for bash, mainly includingexit, less, LP, Kill, CD, PWD, FC, FG, etc.

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Linux-linux Command and Shell