What is a file in linux

What is a file in Linux

1. All content in Linux is in the form of a file Save and manage, that is: everything is a file.

Ordinary files are files.

Directories (called folders under win) are files.

Hardware devices (keyboards, hard drives, printers) are files.

Socket, network communication and other resources are also files.

2. File type:

1) Ordinary files

Similar to mp4, jgp, html, files that can be used directly Ordinary files.

2) Directory files

For users who are accustomed to the win system, it may not be easy to accept that directories are files.

In Linux systems, directory files contain the file names of each file in this directory and pointers to these files. Opening a directory is equivalent to opening a directory file.

That is: as long as you have permission, you can access any file in the directory at will.

vim directory name

3) Character device files and block device files

are usually hidden in the /dev/ directory and are only used when reading devices or interacting with peripherals will be used.

For example: the disk optical drive belongs to the block device file, and the serial device belongs to the character device file.

4) Socket file (socket)

Socket files are generally hidden in the /var/run/ directory and are used for network communication between processes.

5) Symbolic link file (symbolic link)

is similar to the shortcut in win, which is a pointer to another file (soft link).

6) Pipe file (pipe)

is mainly used for inter-process communication.

For example: Use the mkfifo command to create a FIFO file, and at the same time enable process A to read data from the FIFO file, enable process B to write data from the FIFO file, and read as you write.

3. The pros and cons of everything being a file:

Unlike the Windows system, the Linux system does not have as many drive letters as C drive, D drive, and E drive, only one Root directory (/), all files (resources) are stored in a tree directory structure with the root directory (/) as the root of the tree.

(1)The most obvious benefit of this is that developers only need to use a set of APIs and development tools to access most resources in the Linux system. To give a

simple example, almost all reading operations (reading files, reading system status, reading sockets, reading PIPE) in Linux can be performed using the read function; almost all changes (changing files, changing the system Parameters, writing socket, writing PIPE) operations can be performed using the write function.

(2) The disadvantage is that any hardware device must be mounted to a directory under the root directory, otherwise it cannot be used. We know that Linux itself has a file directory structure with the root directory as the root of the tree. The same is true for each device. They are independent of each other. If we want to find the directory structure of the device file through the root directory on Linux, we must combine these two file system directories into one, which is the true meaning of mounting.

Recommended: Getting started with Linux system

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