Linux system learning memorandum 4

Linux system learning memorandum 4 This is the fourth article in this series, mainly involving File System 4.1 files in the Windows operating system series. Our file concepts may be limited to some audio, documents, and so on, in Linux, everything is a file, including processes, serial interfaces, kernel data structures, and process communication channels. This is the design concept of Unix/Linux, which has both advantages and disadvantages. 4.1.1 The path is needless to say. Anyone who has experienced the DOS era or has some experience with linux knows the hierarchical structure of the file system, note that each part of the path name cannot exceed 255 characters, and the total length of the path is limited. You can know it. It will not exceed this length in most cases. 4.1.2 it is relatively simple to install the file system. To be honest, it is the application of the mount command. 4.2 The file tree is organized in a tree directory in the operating system. Let's take a look at the figure below. 4.3 file type, which is commonly used in the WIN series. In LINUX, there are seven types of interfaces, including: 1. Common files; 2. directories; 3. character device files; 4. Block device files; 5. Local interface set; 6. Famous pipelines (FIFO); 7. Symbolic Links; different file types correspond to different system symbols in the system. For example, the directory is d and the symbolic link is l. The following describes two parts: 4.3.1 socket sockets are connections that allow processes to communicate in a "clean" manner. Sockets are directory items visible to other processes, but processes outside the communication connection cannot read and write them. 4.3.2 famous pipelines allow communication between two processes running on the same host. That is, the "FIFO file ". 4.4 file attributes in linux, the ls command may be very commonly used. We can see the first nine letters through ls-al. This is the File Permission bit, relatively basic knowledge. If you are not clear about it, you can search for it by yourself. In the file attributes section, attributes and groups are also involved, that is, who the file belongs to and which user group the file belongs, at the same time, remember the chmod and chown commands that change permissions and groups.