Lecture 2: The file system Hands-on Unix System Administration DeCal 2012-01-30 1 / 19 Review ❖ Basic programs ❖ Basic commands File hierarchy Filesystems File types Review 2 / 19 Basic programs Review ❖ Basic ● pwd programs ❖ Basic commands ● cd File hierarchy Filesystems ● File types ls ● cp, mv ● less, vi 3 / 19 Basic commands Review ❖ Basic ● man, --help programs RTFM: command line ❖ Basic commands option File hierarchy Filesystems ● input: command line options, stdin File types ● output: stdout, stderr ● manipulate with pipes (|), redirection (>, >>), and substitution (‘) 4 / 19 Review File hierarchy ❖ Windows ❖ *nix concept ❖ Looking under / ❖ Looking under / more File hierarchy Filesystems File types 5 / 19 Windows Review ● File hierarchy each storage device has a drive letter, ❖ Windows A:\ C:\ ❖ *nix concept e.g. for floppy, for hard disk, ❖ Looking under / etc. ❖ Looking under / more ● Filesystems important directories File types ✦ C:\Windows ✦ ”C:\Program Files” ✦ C:\Users 6 / 19 *nix concept Review ● File hierarchy “simplicity through expression” ❖ Windows ❖ *nix concept 1 ❖ Looking ● everything starts from the root : / under / ❖ Looking under / more ● excessive (but productive) abbreviation Filesystems File types ● case sensitive 1(not to be confused with /root) 7 / 19 Looking under / /bin/ core binaries /dev/ device files /etc/ systemwide configuration files /home/ home directories (user data) /lib/ core libraries /proc/ procfs interface to kernel 8 / 19 Looking under / more /root/ root’s home directory2 /sbin/to system binaries /tmp/ temporary files /usr/ non-core binaries, libraries, etc. /var/ varying files: logs, user inboxes, running program data, etc. 2(not to be confused with the root /) 9 / 19 Review File hierarchy Filesystems ❖ What is a filesystem? ❖ Examples ❖ Non- disk/flash Filesystems filesystems ❖ RAID ❖ RAID examples ❖ Mounting File types 10 / 19 What is a filesystem? Review ● File hierarchy Each local hard disk can have one or Filesystems more partitions which contain files ❖ What is a filesystem? managed by a filesystem ❖ Examples ❖ Non- disk/flash filesystems ✦ e.g., /dev/sda, /dev/sda1 ❖ RAID ❖ RAID examples ❖ Mounting File types 11 / 19 Examples Review File hierarchy ● Windows (and flash drives) filesystems: Filesystems FAT32, NTFS ❖ What is a filesystem? ❖ Examples ● ❖ Non- Linux: ext3, ext4, btrfs disk/flash filesystems ❖ RAID ● Other Unix: UFS, XFS, ZFS, ReiserFS ❖ RAID examples ❖ Mounting File types 12 / 19 Non-disk/flash filesystems Review ● File hierarchy RAM: tmpfs Filesystems ❖ What is a ● filesystem? network: NFS, SMB ❖ Examples ❖ Non- disk/flash ● FUSE: GmailFS, WikipediaFS filesystems ❖ RAID ❖ RAID examples ❖ Mounting File types 13 / 19 RAID Review ● File hierarchy Redundant Array of Independent Filesystems (Inexpensive) Disks ❖ What is a filesystem? ❖ Examples ● ❖ Non- combine multiple hard drives for speed disk/flash filesystems (striping), capacity, reliability ❖ RAID ❖ RAID (mirroring, parity) examples ❖ Mounting File types 14 / 19 RAID examples Review File hierarchy ● common examples: RAID 0 (striping), Filesystems RAID1 (mirror), RAID5 (parity), RAID ❖ What is a filesystem? 6 (two parity) ❖ Examples ❖ Non- disk/flash filesystems ● nested, e.g., RAID 10 ❖ RAID ❖ RAID examples ❖ Mounting File types 15 / 19 Mounting Review ● File hierarchy file hierarchy crosses filesystem Filesystems boundaries ❖ What is a filesystem? ❖ Examples ● ❖ Non- use mount to mount local or disk/flash filesystems networked stuff on a directory (mount ❖ RAID ❖ RAID point) examples ❖ Mounting File types ✦ can mount regular files too 16 / 19 Review File hierarchy Filesystems File types ❖ Regular files ❖ Other file types File types 17 / 19 Regular files Review ● File hierarchy Windows: filetype extensions Filesystems File types ✦ .exe ❖ Regular files ❖ Other file types ✦ .doc ● Unix: magic tests ✦ man file 18 / 19 Other file types Review ● File hierarchy ls -l Filesystems File types ✦ directories (dir) ❖ Regular files ❖ Other file types ✦ symbolic links (symlink) ✦ devices: character, block ✦ sockets, named pipes (FIFOs) 19 / 19.