Linux Foundation II

A: What is File system filesystem?

Linux file System (FS) is an upside down tree, file management files, easy to find, from the root to find the Wow to the path, do not start from the root lookup called relative path. If each lookup starts at the root, it will be slow.

Second: Hash cache table

command to use the record in the hash cache table, the next time with no longer go to the path to check, directly take the hash table can be, so fast.

Environment variables, define the user's environment, such as the user's font ah. PRINTENV View environment variables.

Three:ls<list>

Lists files, directories, and properties under the specified path

LS parameter description

Ls-l

File type

-: Normal file

D: Catalog file

B: Block device files

C: Note Equipment file

L: Symbolic Link file

P: Command pipe file (pipe)

S: Socket file (socket)

CRW-RW----1 root video, 175 Jul 16:10 Agpgart

File permissions: 9-bit, every 3-bit group, rwx (read, write, executable)

Number of hard links to files

Owner of the file

Genus Group of files

Size of the file (size), in bytes

Timestamp (timestamp): Last Modified Time

Access: Access

Modified: Modify

Change: change,metadata, meta data

-H: Do unit conversions, familiar units

-A: Show hidden files

-A

-D: Display the directory's own properties

-i:inode

-R: Reverse Display

-R: Recursive display

Cd:change Directory

Home directories, home directories, home directory

CD ~username: Enter the home directory of the specified user

CD-: Switch back and forth between the current directory and the previous directory

Command type:

Built-in commands, external commands

Type: display specifies which type to belong to

The man command is divided into chapters, such as Man 1 ls

1: User command

2: System call

3: Library User

4: Special files (device files)

5: File Format (configuration file syntax)

6: Game

7: Miscellaneous

8: Management Commands

Whatis read view read with those man chapters

Man's content:

<>: Required

[]: Optional

...: can occur multiple times

|: Choose one More

{}: Grouping

Flip Screen:

Turn back one screen: space

Turn One screen forward: b

Turn back one line: Enter

Turn One line forward: K

Find:

/keyword: Backwards

N: Next

N: Previous

Document:/usr/share/doc