How to detect whether the USB disk is connected in the Linux system

This article mainly shows you "how to detect whether the U disk is connected in the Linux system", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and learn "how to detect whether the U disk is connected in the Linux system" this article.

Linux's file system is asynchronous, that is, writing a file is not immediately saved to the media (hard disk, USB disk, etc.), but to a buffer, and then saved to the media together when accumulated to a certain extent. If there is no umount to pull out the USB disk illegally, the program does not know, fopen,fwrite and other functions still return correct, know that the operating system to write the media, will prompt Imax O error. However, a lot of data will be lost because of this untimely error report.

In fact, the USB driver makes changes to the system configuration file when the USB flash drive is inserted and unplugged.

For example, the USB flash drive driver will record Attached:Yes or No in / proc/scsi/usb-storage-0/0 when plugged in or unplugged.

By looking at this file, it is not difficult to detect whether the flash drive is inserted or unplugged.

Note: the state of whether the USB disk is inserted or not has nothing to do with whether it is mounted (mount).

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