Use man date to view the details of the date command.
[email protected]:~$ Man Date Date (1) User Commands Date (1) # Please note that above The number in parentheses is name <== the full full name of this command, as shown in date and shows the simple purpose of configuring and displaying the date/time Date-print or set the system date and times Synopsis & lt;== the basic syntax for this command is as follows: Date [OPTION] ... [+format] Date [-u|--utc|--universal] [MMDDHHMM[[CC]YY][.SS]] DESCRIPTION <== details the use of options and parameters that have just been discussed in syntax Displa Y the current time in the given FORMAT, or set the system date. -D,--date=string <== left-D is the short option name, the right--date is the full option name display time described by STRING, not ' now '-F, --file=datefile like--date once for each line of Datefile-r,--reference=file Displa Y the last modification time of FILE .... (omitted in the middle) .... # Found! Below is the detailed data of the formatted output! FORMAT controls the output. The only valid option for the second form specifies coordinated Universal time. Interpreted sequences is: percent a lIteral%%a Locale ' s abbreviated weekday name (e.g., sun)%a locale ' s full weekday name (e.g., sun Day) .... (omitted in the middle) .... Environment <== The environmental parameters associated with this command are like the following description of TZ specifies the timezone, unless overridden by command line Parameters. If Neither is specified, the setting from/etc/localtime is used. AUTHOR <== The author of this order! Written by David MacKenzie. REPORTING BUGS <== have questions please leave a message to the bottom of the email meaning! Report bugs to <[email protected]>. Copyright <== protected by the law! The GPL is used! Copyright? 2006 Free Software Foundation, Inc. This is the free software. Redistribute copies of it under the terms of the GNU general public License The screen that appears, we call him the man page, you can query his usage and related parameter description inside.First, in the first row of the previous table, you can see the following: "Date (1)", date we know the name of the command, then (1) What does it mean? He represents the meaning of "commands that can be used by the general user"! He can help us understand or directly query the relevant data. The meaning of several common numbers is this:
Code |
Representative content |
1 |
Commands or executable files that the consumer can manipulate in a shell environment |
2 |
System core can call functions and tools, etc. |
3 |
Some common functions and function libraries (library), most of which are C (libc) |
4 |
Description of the device file, usually files in/dev |
5 |
The configuration file or the format of some files |
6 |
Game (games) |
7 |
Conventions and protocols, such as Linux file systems, network protocols, ASCII code, and more |
8 |
Administrative commands available to system administrators |
9 |
Documents related to Kernel |
The above table contents can be described in more detail using "Man 7 Man". In the future, if you use the man page to view some data, you will know what the basic meaning of the command/file represents. For example, if you give a "man null", the first line that appears is: "Null (4)", compared to the above number meaning, originally null unexpectedly is a "device file"!
1, 5, 8 of these three numbers are particularly important in the table above.
The contents of man page are divided into several parts to introduce the command! It's the first man's date in the table, with name as the start, and finally a see also to end. Basically, the man page is roughly divided into the following sections:
Code |
Content Description |
NAME |
Short command, Data name description |
Synopsis |
Brief Introduction to command release syntax (syntax) |
DESCRIPTION |
A more complete description, this part of the best look carefully! |
OPTIONS |
For the synopsis section, there is an enumeration of all the available option descriptions |
COMMANDS |
Commands that can be placed in this program (software) when the program (software) is running |
FILES |
Some of the files used or referenced or linked to by this program or data |
See ALSO |
You can refer to this command or the data have related other instructions! |
EXAMPLE |
Some examples that can be consulted |
BUGS |
Are there any related bugs! |
- First look at the name of the project, a glance at the meaning of this data;
- Take a look at description, this section will refer to a lot of relevant data and use of time, from this place can learn a lot of small details it;
- And if the command is actually familiar (for example, date above), then the main thing is to query the options section! You can know the meaning of each option so that you can release the command content of the comparison details!
- Finally, let's look at what else can be used with this data? For example, the see also above tells us that we can also use "info coreutils date" To further review the data;
- Some of the instructions will also list the relevant documents (Files section) to provide our reference! These are all very helpful!
Man page Common keys
Keys |
To work |
Space key |
Turn down one page |
[Page down] |
Turn down one page |
[Page up] |
Turn up one page |
[Home] |
Go to the first page |
[End] |
Go to the last page |
/string |
Search "Down" for string, and if you want to search for Lucifer, enter/lucifer |
? string |
Search "Up" for string |
n, n |
use/or? To search for a string, you can use N to continue the next search (either/or), using N for the "reverse" search. For example, I/lucifer search lucifer string, then can n continue to query, with N up query. If lucifer query up lucifer string, then I can use N to continue" up "query, with n reverse query. |
Q |
End this man page. |
Question 1: Can you find out if there are any documentation related to the "Man" command in the system?
With the-f option, you can get more information about man, and the above results indicate the (number) content, for example, the second line of "Mans (7)" indicates that there is a description file for the person (7)
The search order is recorded in the/etc/man.conf this configuration file, the first search for the description file, will be displayed first! Generally speaking, you will find the one with the smaller number first! Because of the sort of relationship Ah! So, the man will be the same as 1 mans!
Question 2: Find out the system's documentation, as long as the word "man" will be listed in this description.
Also, Whatis equivalent to man-f,apropos equivalent to Man-k
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