Key Linux File Systems
- ext2: Older, no journaling. Good for low-overhead needs like USB drives.
- ext3: Adds journaling (better crash recovery) compared to ext2.
- ext4: The default on most Linux systems, offering improved performance, reliability, and large file support.
- Btrfs: Known for advanced features like snapshots, checksums, and data integrity checks.
- XFS: Great for handling large files with high I/O performance.
- NTFS: Mainly for Windows, but Linux can use it for compatibility with dual-boot systems or external drives.
File System Hierarchy & Structure
- Linux uses a hierarchical directory structure, where directories contain files and subdirectories.
- Inodes: Store metadata about files and directories (permissions, ownership, etc.), but not actual file data.
Common File Types
- Regular files: Can store text, binary data, images, etc.
- Directories: Contain files or other directories.
- Symbolic Links (Symlinks): Shortcuts pointing to other files or directories, providing quick access without duplicating files.
Disk Management Tools
- fdisk: A tool for partitioning disks and displaying partition tables.
For example:
sudo fdisk -lgparted and GParted: Alternatives for graphical disk partitioning.
Mounting File Systems
Mounting makes a partition accessible under the directory structure. You can mount partitions using:
sudo mount /dev/sdb1 /mnt/usbTo automatically mount a file system at boot, entries are added to /etc/fstab.
Unmounting File Systems
To unmount, ensure no processes are using the filesystem. Use:
**sudo umount /mnt/usb**If processes are using the file system, use lsof to identify them.
Automating Mount/Unmount
You can configure mount and unmount behavior via /etc/fstab:
- Add noauto to prevent mounting at boot.
- Add the noauto option to automatically unmount at shutdown.
Permissions and Ownership
Linux permissions allow defining access control for files, specifying who can read, write, or execute them. Users, groups, and others may have different levels of access.