Linux Fundamentals 1

Ls

-L Long format

File type: the

-Ordinary files

D; catalog file

B: Block device files (blocks)

c; Character device files (character)

l; Symbolic link files (symbolic link file)

p; command pipe file (pipe)

s; socket file (socket)

File permissions: 9 bits per 3-bit group, each group: rwx (Read, write, execute)

Number of hard links to files

Owner of the file

Genus Group of files

File size (size), default unit is byte

Timestamp (timestamp), Last modified time

Access: Access

Modified: Modify file contents are changed

Change: The change is metadata, the meta-data

-H: For unit conversions

-A: Show hidden files starting with.

. Represents the current directory

.. Represents the parent directory

-A: Show hidden files but not include. and.

-D: Display the directory's own properties

-i:index node, Inode displays the miniature nodes of the file

-R: Reverse Display

-R: Recursive (Recursive) display

Cd:change Directory Switch Directories

Home directories, home directories, home directory

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

CD-: Switch back and forth from the previous directory to the current directory

Command type:

Built-in command (shell built-in), internal built-in

External command: There is an executable file corresponding to the command name in a path on the file system

Environment variables: named memory space

Assigning values to variables

Name=jerry

Path: separated paths with colons

O (1)

Type: Shows which type the specified command belongs to

Hash: View Cache,

Data: Time Management

LINUX:RTC (really time clock)

NTP: Network Time Protocol

Hardware Clock Hwclock

System clock

Get help with the use of commands;

Internal command:

Help COMMAND

External command:

COMMAND--help

Command manual: Manual

Mans COMMAND

Whatis command--view commands appear in the first few chapters

Sub-chapters:

1. User commands (/bin,/usr/bin,/usr/local/bin)

2. System calls

3. Library users

4. Special documents (equipment files)

5. File format (configuration file syntax)

6. Games

7. Miscellaneous (Miscellaneous)

8. Management commands (/sbin,/usr/sbin,/usr/local/sbin)

<>: Must be given the

[]: Optional content

... : Multiple occurrences can occur repeatedly

: Choose one More

{}: Grouping has no special meaning

Mans:

Name: command names and features brief description

Synopsis: Usage notes, including available options

DESCRIPTION: A detailed description of the command function, which may include the meaning of each option

Options: Explaining the meaning of each option

Files: Related configuration file for this command

BUGS:

EXAMPLES: Use Cases

See ALSO: Another reference

Flip Screen:

Turn back one screen: space

Turn One screen forward: b

Line backward: Enter

Forward line: K

Find:

/keyword: Backwards

N Key: Next

N Key: Previous

? KEYWORD: Forward

N Key: Next

N Key: Previous

Exit: Q

Online Documentation:

Info Conmmand

Document:/usr/share/doc

Google

Apache,hadoop,

Hwclock Viewing hardware time

-s hardware clock to System

-W system clock to hardware

Linux Fundamentals 1