Wiki

User Tools

Site Tools

Trace: • start
linux:files_system

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
linux:files_system [2020/10/27 09:38] – 192.168.1.1linux:files_system [2022/07/09 13:44] (current) – 185.192.71.121
Line 1: Line 1:
 ====== Linux - Files System ====== ====== Linux - Files System ======
 +
 +<code>
 +/              Root
 +-> /bin        User Binaries
 +-> /boot       Boot Loader Files
 +-> /dev        Device Files
 +-> /etc        Configuration Files
 +-> /home       Home Directories
 +-> /lib        System Libraries
 +-> /media      Removable Devices
 +-> /mnt        Mount Directory
 +-> /opt        Optional Add-On Applications
 +-> /proc       Process Information
 +-> /sbin       System Binaries
 +-> /srv        Service Data
 +-> /tmp        Temporary Files
 +-> /usr        User System Resources
 +-> /var        Variable Files
 +</code>
 +
 +----
  
 {{:linux:linux-file-system.jpg?800|}} {{:linux:linux-file-system.jpg?800|}}
Line 107: Line 128:
 </code> </code>
  
-  * File name **/usr/bin/perl** really points to inode number **38928562**.+  * File name **/usr/bin/perl** points to inode number **38928562**.
   * Another name **perl5.26.1** points to the same inode number.   * Another name **perl5.26.1** points to the same inode number.
  
Line 113: Line 134:
 **NOTE:**  Each inode may have many names! **NOTE:**  Each inode may have many names!
  
-As can be seen above, both `perl` and `perl5.26.1`, point to the same inode number `38928562`.+As can be seen above, both **perl** and **perl5.26.1**, point to the same inode number **38928562**.
  
 Each file name is mapped to only one single inode number, but one file inode number may have many names that map to it. Each file name is mapped to only one single inode number, but one file inode number may have many names that map to it.
Line 130: Line 151:
 Directories map file system names to inode numbers.  In this example, file system name **perl** is mapped to inode number **38928562** that contains the actual data. Directories map file system names to inode numbers.  In this example, file system name **perl** is mapped to inode number **38928562** that contains the actual data.
  
-When you access the `perl` program by name, the system finds the `perl` name in a directory, paired with the inode number `38928562` that holds the actual data, and then the system has to go elsewhere on disk to that inode number `38928562` to access the data for the `perl` program.+When you access the **perl** program by name, the system finds the **perl** name in a directory, paired with the inode number **38928562** that holds the actual data, and then the system has to go elsewhere on disk to that inode number **38928562** to access the data for the **perl** program.
 </WRAP> </WRAP>
  
Line 176: Line 197:
  
   * The attributes of a directory inode apply only to that directory itself, not to the objects named *in* the directory, which have their own inodes.   * The attributes of a directory inode apply only to that directory itself, not to the objects named *in* the directory, which have their own inodes.
-  * The attributes of the objects named *in* the directory -- such as names of files or sub-directories -- are *not* stored in the directory; they are stored in the individual inodes of those things.+  * The attributes of the objects named **in** the directory -- such as names of files or sub-directories -- are **not** stored in the directory; they are stored in the individual inodes of those things.
  
 </WRAP> </WRAP>
Line 291: Line 312:
 That directly data is simply a list of names and inode numbers. That directly data is simply a list of names and inode numbers.
  
-The directory inode contains attribute information about the *directory*, itself, not about the things named *in* the directory. (Use **ls -ld** to see the attributes of the directory inode itself.)+The directory inode contains attribute information about the **directory**, itself, not about the things named **in** the directory. (Use **ls -ld** to see the attributes of the directory inode itself.)
  
 <WRAP info> <WRAP info>
Line 322: Line 343:
 A Unix directory is only a list of pairs of names and associated inode numbers. A Unix directory is only a list of pairs of names and associated inode numbers.
  
-The attribute information about an item named *in* a directory -- the type, permissions, owner, etc. of the thing -- is kept with the inode associated with the thing, not in the directory itself.+The attribute information about an item named **in** a directory -- the type, permissions, owner, etc. of the thing -- is kept with the inode associated with the thing, not in the directory itself.
  
 Reading a Unix directory tells you only some names and inode numbers; you know nothing about the types, sizes, owners, or modify times of those inodes unless you actually go out to each separate inode on disk and access it to read its attributes. Reading a Unix directory tells you only some names and inode numbers; you know nothing about the types, sizes, owners, or modify times of those inodes unless you actually go out to each separate inode on disk and access it to read its attributes.
Line 416: Line 437:
 ---- ----
  
-===== Tracing Inodes in Pathnames -- ASCII Art =====+===== Tracing Inodes in Pathnames ===== 
  
-Below is an ASCII Art diagram of some directories and a hard-linked file with two names. 
  
 ==== Slashes separate names in pathnames ==== ==== Slashes separate names in pathnames ====
Line 453: Line 474:
 ==== Names reside above the things they name ==== ==== Names reside above the things they name ====
  
-Below is a file system diagram written correctly, with the names for things shown in the directory one level *above* the things to which the names actually refer.+Below is a file system diagram written correctly, with the names for things shown in the directory one level **above** the things to which the names actually refer.
  
 Each box represents an inode; the inode numbers for the box are given beside the box, on the left. Each box represents an inode; the inode numbers for the box are given beside the box, on the left.
Line 478: Line 499:
                       |  The ROOT directory itself does not have a name, because there is no directory above it to give it a name!                       |  The ROOT directory itself does not have a name, because there is no directory above it to give it a name!
                       V                         V  
-        +----+-----+---------------------------------------------------++        +----+-----+--------------------------------------------------------+
     #5  |. 5 |.. 2 | peter 31 | virginia 36 | felix 39 | abcd0001 21 | ...  |     #5  |. 5 |.. 2 | peter 31 | virginia 36 | felix 39 | abcd0001 21 | ...  |
-        +----+-----+--v------------------------------------------------++        +----+-----+--v-----------------------------------------------------+
                       |  The inode #5 above is the "home" directory.                        |  The inode #5 above is the "home" directory. 
                       |  The name "home" isn't here; it's up in the ROOT directory, above.                       |  The name "home" isn't here; it's up in the ROOT directory, above.
Line 488: Line 509:
     #31 |. 31|.. 5 | test 12 | temp 15 | Documents 8 | Downloads 7 | demo 6 | ... |     #31 |. 31|.. 5 | test 12 | temp 15 | Documents 8 | Downloads 7 | demo 6 | ... |
         +----+-----+--v-----------------------------------v-----------------------+         +----+-----+--v-----------------------------------v-----------------------+
-                      |  The inode #31 above is the "     | +                      |  The inode #31 above is the       | 
-                      |  peter" directory.                |+                      |  "peter" directory.               |
                       |  The name "peter" isn't here;     |                       |  The name "peter" isn't here;     |
                       |  it's up in the "home" directory, |                       |  it's up in the "home" directory, |
                       |  above.                           |                       |  above.                           |
                       |  This directory has the names     |                       |  This directory has the names     |
-                      |  "test " and "Downloads" in it    |+                      |  "test " and "Downloads" in it.   |
                       |                                   V                       |                                   V
-        +----+-----+--|-------------------------------------------+ +        +----+-----+--|------------------------------------------+ 
-    #7  |. 7 |.. 31|  |  test 12 | morestuf 123 | junk 99 | ... | +    #7  |. 7 |.. 31|  |  afile 12 | morestuf 123 | junk 99 | ... | 
-        +----+-----+--|-------v-----------------------------------++        +----+-----+--|-------v----------------------------------+
                       |       |  The inode #7 above is the "Downloads" directory.                       |       |  The inode #7 above is the "Downloads" directory.
                       |       |  The name "Downloads" isn't here;                        |       |  The name "Downloads" isn't here; 
Line 636: Line 657:
 The box below represents the actual disk space given to the `test` file, inode `#12`: The box below represents the actual disk space given to the `test` file, inode `#12`:
  
-        *-----------*+        +-----------+
     #12 | file data |     #12 | file data |
-        *-----------*+        +-----------+
  
 The name `test` for this inode isn't in this inode; the name `test` is up in the `peter` directory. The name `test` for this inode isn't in this inode; the name `test` is up in the `peter` directory.
linux/files_system.1603791493.txt.gz · Last modified: 2020/10/27 09:38 by 192.168.1.1
Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki