fstab文件的作用和格式
文件/etc/fstab存放的是系统中的文件系统信息。当正确的设置了该文件，则可以通过"mount /directoryname"命令来加载一个文件系统，每种文件系统都对应一个独立的行，每行中的字段都有空格或tab键分开。同时fsck、mount、umount的等命令都利用该文件。
The fstab (or file systems table ) file is a system configuration file commonly found at /etc/fstab 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 are not necessarily 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While fstab is still used for basic system configuration, for other uses it has been superseded by automatic mounting mechanisms.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.
The fstab file is read by programs that work with disk partitions and other file systems and is not automatically maintained . Instead it is written by the system administrator or sometimes by an operating system installation program.
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