tailieunhanh - Red Hat Linux 7.2 Bible, Unlimited ed phần 2

Nhiều người trong số các lệnh này được mô tả trong phần còn lại của chương khi biểu tượng và cửa sổ trên màn hình máy tính, bạn gõ lệnh để chạy hầu hết các máy tính. Trên hệ thống UNIX, mà Red Hat Linux được bắt nguồn, | I just showed a few commands designed to familiarize you quickly with your Linux system. There are hundreds of other commands that you can try that are contained in directories such as bin and usr bin. There are also administrative commands in sbin or usr sbin directories. Many of these commands are described in the remainder of this chapter. Understanding the Red Hat Linux Shell Before icons and windows took over computer screens you typed commands to run most computers. On UNIX systems from which Red Hat Linux was derived the program used to interpret and manage commands was referred to as the shell. The shell provides a way to run programs work with the file system compile computer code and manage the computer. Although the shell is less intuitive than common GUIs most Linux experts consider the shell to be much more powerful than GUIs. Because shells have been around for so long many advanced features have been built into them. Many old-school Linux administrators and programmers primarily use a GUI in their work as a means of opening lots of shells. The Red Hat Linux shell illustrated in this chapter is called the bash shell which stands for Bourne Again SHell. The name is derived from the fact that bash is compatible with the first UNIX shell the Bourne shell represented by the sh command . Other popular shells include the C Shell csh which is popular among BSD UNIX users and the Korn Shell ksh which is popular among UNIX System V users. Linux also has a tcsh shell a C shell look-alike and an ash shell another Bourne shell look-alike . Although most Red Hat Linux users have a preference for one shell or another when you know how to use one shell you can quickly learn any of the others by occasionally referring to the shell s man page for example type man bash . In Red Hat Linux the bash shell is roughly compatible with the sh shell. Caution When you run the sh shell in Linux a link to the bash shell is actually invoked instead of the sh shell. To have bash .