fstab (after file systems table) is a system file commonly found in the directory /etc on Unix and Unix-like computer systems. In Linux, it is part of the util-linux package. The fstab file typically lists all available disk partitions and other types of file systems and data sources that may not necessarily be disk-based, and indicates how they are to be initialized or otherwise integrated into the larger file system structure.
The fstab file is read by the mount command, which happens automatically at boot time to determine the overall file system structure, and thereafter when a user executes the mount command to modify that structure. It is the duty of the system administrator to properly create and maintain the fstab file.
While fstab is used for basic system configuration, for other uses, it has been superseded by automatic mounting mechanisms.
The file has other names on some versions of Unix; for example, it is found at /etc/vfstab on Solaris systems.