Linux Learning (1), Linux Learning (

Linux Learning (1), Linux Learning (

1. What is shell and bash? What is the difference between them?

Shell is a user interface that interacts with Linux.

Bash is a special case of shell, or an implementation.

Bash: command line user interface application!

The common command line user interface is bash!

 

2. What is Linux kernel:

Baidu Encyclopedia: Linux is an open-source computer operating system kernel. It is a Unix-like operating system written in C language that complies with POSIX standards.

Simply put, it is the heart of Linux.

 

3. What is a database?

A large number of libraries exist on windows and linux platforms.

Essentially, a library is a binary form of executable code that can be loaded into the memory for execution by the operating system.

 

There are two types of libraries in linux: static library and shared library (dynamic library ).

The difference between the two lies in that the code is loaded at different times.

The code of the static library has been loaded into the executable program during compilation, so the size is large.

The code of the shared library is loaded into the memory only when the executable program runs. It is only referenced in the compilation process, so the code size is small.

 

4. Common file formats in Linux:

L starts with: Link file

D starts with directory files.

C starts with a character device file (character file)

B starts with a block device file (byte file)

 

5. File User Permissions:

Rwx

Owner group others

R: read Permission, w: write permission, and x: Execution permission.

 

6. Use help to view the internal information of the command, and use man to view the external information.

Help is the help of Internal commands, such as cd
Man is the help of external commands, such as ls

 

7. Create a file. You can use touch or echo

Touch a.txt creates an empty file

While echo creates a file with content

 

Echo "hello"> a.txt creates a file named a.txt and writes hello to the file.

Echo "haha"> a.txt is the content appended to the end of the.txt file.

 

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