Linux Self-study note-Basic command date,cal, etc.

Riding, behind;

Date command:

We can come to man. Date command, which can be seen in the meaning of date-print or set the system date and time, we illustrate the date command from the following aspects.

1. Show Time

Date[option] ... [+format]

format : Format Symbols

%d :

%F :

%T :

Enter a separate date command on the screen to display the system time:

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We can also display the time display format we want:

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2. set the time

Date[-u|--utc|--universal] [MMDDHHMM[[CC]YY][.SS]]

MM: Month

DD: What date

hh: hours

mm: minutes

YY: Two-bit year

CCYY: four-bit year

. SS: seconds

The following example shows the process of modifying a time using the date command:

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Linux Two kinds of clocks

System clock: The timing of the CPU operating frequency by the Linux kernel;

Hardware clock:

Hwclock : Display hardware clock;

- S ,--hctosys

- W ,--SYSTOHC

Cal instruction

cal-displays a calendar Show Calendar

1. Show Calendar

Cal [-SMJY13] [[[Day] month] year]

Enter a separate CAL directive on the screen to display the calendar for the current system time Month:

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You can also display calendars for a full year and any month of any year:

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Directory Management Class command: CD pwd ls mkdir rmdir tree

mkdir :

mkdir-make Directories Create a directory

mkdir [OPTION] ... DIRECTORY ...

- P : does not error when present, and automatically creates the required directories;

- v : Displays detailed information;

- m MODE : Specify permissions directly when creating a directory

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Tree :

tree-list contents of directories in a tree-like format. The contents of the display directory are in the form of a tree

tree [-ADFGHILNOPQRSTUVXACDFNS] [-llevel [-R]] [-H basehref] [-t title] [-o filename]

[--nolinks] [-P pattern] [-I pattern] [--inodes]  [--device]  [--noreport] [--dirsfirst]

[--version] [--help] [--filelimit #] [Directory ...]

- D : Displays only directories;

- L: Specifies the number of levels displayed;

- P Pattern : Displays only the path that is matched by the specified pattern;

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rmdir :

Rmdir-remove Empty Directories removing an empty directory

rmdir [OPTION] ... DIRECTORY ...

- v : Display Process

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Practice:

(1) How to create/tmp/x/y1,/tmp/x/y2,/tmp/x/y1/a,/tmp/x/y1/b,/tmp/x/y2/a,/tmp/x/y2/b

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(2) How to create X_m,y_m, X_n, Y_n

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(3) How to create/tmp/bin,/tmp/sbin,/tmp/usr,/tmp/usr/bin,/tmp/usr/sbin

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Linux Self-study note-Basic command date,cal, etc.