mount (Unix)

In Unix-like operating systems, mount refers to the process of making a storage device or file system accessible at a specific location (a mount point) within the file system hierarchy. The mount command is used to attach a file system, typically residing on a hard drive, USB drive, network share, or other storage media, to a designated directory in the existing directory structure, effectively merging the new file system into the existing one.

The mount point is a directory within the already accessible file system. Any files or directories previously present at that mount point become inaccessible while the new file system is mounted. When the file system is unmounted, the original contents of the mount point directory become visible again.

The mount command requires root privileges to execute in most cases. It typically takes arguments specifying the device or file system to be mounted, the mount point, and optionally, the file system type (e.g., ext4, NTFS, NFS) and other options, such as read-only or read-write access.

The /etc/fstab file is often used to define file systems that should be automatically mounted at boot time. This file contains information about the devices, mount points, file system types, and mount options, allowing the system to automatically set up the file system structure upon startup.

Unmounting, the reverse process of detaching a mounted file system, is accomplished using the umount command. This detaches the file system from the specified mount point, making the files and directories on the mounted device inaccessible until it is mounted again. Before unmounting, it is crucial to ensure that no processes are currently accessing files within the mounted file system, as this can lead to errors or data corruption.