The zero-based Linux seventh chapter

The zero-based Linux seventh chapter

Students early ~ ~ Small series and to update the blog ~

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(Still in the happy play of the classmate) "Small series of adults ... It's not time to update yet! ”

(whispering) "not normal, so lazy little compilation will be updated in advance, probably Saturday Sunday to advance Valentine's Day"

(whispering) "No, no, it's impossible to have a girlfriend, you see, every day bullying passers-by"

(The passers-by who are making notes suddenly dark down, under the consciousness of the use of strength, broken out of the nib from said above the boy's face across the sentence.) The whisper of the voice stopped ... ) (Spit Groove: Yuck!) Small language expression ability really poor)

Waste What words! Come on, sit down!! Just want to play all day ! 650) this.width=650; "src=" https://s1.51cto.com/wyfs02/M02/00/B1/wKiom1mb5yezThF6AAAhlDcgC-o202.gif "title="% Z6WDTN (875dhh63 (e4oux4.gif "width=") height= "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:50px;height:50px; " alt= "Wkiom1mb5yezthf6aaahldcgc-o202.gif"/>

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(↑ casual classmates)

Students in this state how can do it ~ ~ This is a waste of their time Oh ~ ~ ~ and time is life.

A Zakin said, "Life is precious, human life is only once, the life of people should be so spent: not because of no study and remorse, not because not to share learning and shame, so that in his deathbed can also proud of the chest, loudly shout: ' I put my whole life and all the energy, are dedicated to the world's most magnificent and great cause---for mankind to meet the desire to pursue knowledge and struggle! ’”

Cough ... The little knitting is far away. In fact, small series of ~~650) this.width=650; "Src=" https://s1.51cto.com/wyfs02/M00/00/B3/wKiom1mb8smzJ54YAAAFBVjTNo4711.jpg " Title= " -17c23f93a77fdd80.jpg" width= "height=" border= "0" hspace= "0" vspace= "0" style= "width:35px;height:35px;" alt= "Wkiom1mb8smzj54yaaafbvjtno4711.jpg"/>

OK ~ ~ ~, the previous chapter on the file command to see the type of a document,Whatis command to see the description of the command, as well as commands --help and help - command to get help with the use of external commands and internal commands, and also the type command to see the types of commands. Oh yes ~ ~ There are still small series of homework left.

About two homework, small series will not say more ~ ~ Do not understand the words may be a little hazy in the future Oh ~ ~

Then, the small part of the next start to talk about the content of this chapter: the previous chapter on how to view the command more detailed help information, in fact, the last chapter of the two to get help is just foreshadowing, this is the key Oh ~ ~

Well, since the above two commands are not very reliable, then which of the command to get help is reliable?? Man is the reliable ~ ~ Yes, it is men ~ ~ So, small series is the most reliable ~ ~ ~

Let's start with the whatis command to See the description of the man command.

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There are three help chapters to find man in Whatis , according to the description, we can probably determine that the first chapter is the man we need to see.

Man: An online reference manual for an interface

Now, let's use this command to look at the use of the man command itself help

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When we opened it, we found that the use help shown in the man Help document was more detailed, and a lot (a small part of it only took a fraction), how do we look at so many and dazzling documents? What is included in the content?

What is included in the Man Help manual:

NAME: Functional description, which is the description of the command

Synopsis: Syntax format. That is, how to use the command correctly. (Note that there are some special symbols in this format, such as: [] means the content of the;< > denotes the content that must be, A|b|c said that in a, B, c three select one; "..." means that similar content can appear more than one)

descrirtion: Function description. (Here the description and the small part of the description is not the same OH ~ ~ The description here is a very detailed introduction of the command to query.) And the description of the small part of the above is very simple to say that this command is used to do something. ）

option: Options for this command. (at the beginning of the series, the option of a command determines the function of the command, which shows all the options for the command to be queried, and what the effect of these options is attached to)

EXAMPLES: Use the example. (Here's how to use the options for the commands you want to query)

AUTHOR: Author. (well, this little part doesn't explain it.)

BUGS: How to report a bug in a program. (When we use commands, some of the commands have bugs that cause some functionality to fail, and if you want the author to know and fix it, you can get feedback by the way you give it.) But the situation is very rare to see ~ ~)

See ALSO: Reference. (the reference here is not to give a reference to how the command is queried, but rather to tell us which section of the command is being queried, which has more than one mention of the chapter, either here or in the section mentioned in the previous chapter, which is the section of the man document.) The description of the commands collected by Whatis is a database created by querying the man document. As to what these different chapters are, the small part will be explained below. ）

Historical: The history of the command being queried. (This does not need a small explanation ~)

The above is the man command to help the content provided in the document, of course, there are some, the small part is not listed ~ ~ As for the man document chapter, like a book in the directory, each directory has a different content. Small series has always been said that all the files in Linux, so the man command to query the help of course also in the file.

So where are these help documents, since they are files?

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The chapters in the /usr/share/man/ directory where the man command is stored, while the whatis command creates the database, actually accesses these man1 man2....man9 These help documents to record the descriptions in NAME in these man documents in the database. At the same time, some commands are not only present in a single man document, but Whatis also records which man documents they exist in while gathering descriptions of these commands.

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Small series again with Whatis to see the description of the Man command, when the description of the command, the command will be followed by a parenthesis, and the number in parentheses is to query the corresponding chapter of the command, here we see the man command exists with three chapters.

Man's help document has so many chapters, but from man1 man2 .... What do these chapters correspond to?

1: User Command Help

2: System call Help

3:C Library Call Help

4: Device files and special files Help

5: File format (configuration file format)

6: Game Use Help

7: Miscellaneous

8: Management tools and Guardian tools

9:linux Kernel API

And when we use the man command to see the help, the chapters will be displayed, such as the chestnut on the top of the table. Use the man command to see the help of the man command

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We can see the upper left hand corner showing man (1) This means that the help for the man command we are currently viewing is the first chapter of the view, and the Help for the man command shown in the Whatis View Man command is also in the 7th chapter, when we want to see the 7th Chapter How to do?? The man command displays only the previous chapters by default.

Man # command: You can view the contents of the specified # Chapter

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Now we see that the upper-left corner is man (7) , indicating that we are now viewing the use of the Man command in the 7th chapter of the Help

At the same time, not only Whatis can query the commands in which chapters, the Man command comes with the option also has this function

MAN-F command: See which chapter of the command is present

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Passer-by: "Oh??" As the Whatis command shows ~ ~ "

Yes, yes. So, men (man) is very reliable ~ Oh no ~ ~ is a small series but very reliable ~ ~ (Spit Groove: What is your relationship)

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(↑ The expression of a passer-by)

Finished, passers-by ~ ~ You have changed ~ ~ You were not like this before .... 650) this.width=650; "src=" https://s1.51cto.com/wyfs02/M01/00/B6/wKiom1mcHzOhiLcgAAAKM2GPkhE303.jpg "title="]8x9% T}}nalva~rlwo18vic.jpg "width=" "height=" "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:60px;height:36px; "alt=" Wkiom1mchzohilcgaaakm2gpkhe303.jpg "/> Immediately Valentine's Day, you can not give me a little warmth ....

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(↑ passers-by armour)

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OK ~ ~ We continue class (Spit groove: I am tired of x, you face than the weather is fast!) ）

The man command actually has a search function that searches through keywords, that is, even if we forget what the command is, just remember that there are several words in the Help document where this command is located:

Man-k keyword: View all chapters that contain the specified keyword

Below, the small series to experiment, casually enter a keyword

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Wow ~ ~ so many ~ ~ Well, in fact there is no use, students just need to know that there is this function on the line ~ ~

When we look at the Help documentation for a command, the help document is very informative, so the question is, how do we do it when we open the Help manual??

Man Help document operations:

Flip Screen:

SPACEBAR : Flip a screen to the end of the file (the current terminal can display the content is called a screen)

B: Flip a screen to the beginning of the file

Ctrl+d: Turn half screen at the end of the file

Ctrl+u: Turn half screen at the beginning of the file

Enter: Flip a line to the end of the file

K: Flip a line to the beginning of the file

G: Jump to the last line

# (Specify number) G: Jump to the specified row

(↑ In fact, those who turn a line, you can directly use the keyboard arrow keys to turn one line at a time)

That's how we turn the page after we open the help document, so when the content is particularly special, we don't want to turn the page, and we know which option we want to see what to do?? Don't worry ~ ~ Man command is very powerful ~ ~ When we open the man's help document and want to look directly at what you need, you can search the document for keywords:

Text Search:

/keyword (Specify keyword): Look up from the beginning of the file to the end of the file file, not case-sensitive

？ Keyword (Specify keyword): From the end of the file to the beginning of the file, look, case-insensitive

When we query the results, in general, to query the keyword in the document multiple times, we need to confirm which is what we want, so we need to match to the keyword to look at. At this point, we can use:

N: Jump to next keyword (same as find command direction)

N: Jump to next keyword (opposite to find command)

What do you mean by the same direction and the opposite of the Find command? For example, when we use text search /keywords to find the keyword to query, the/keyword command looks for the end of the file from the beginning of the file, and we use N to see the matching keyword. The order is viewed from the end of the file to the beginning of the file, and n is viewed from the beginning of the file to the end of the file.

When we have finished querying the use of the command help, to exit the Help document can be used:

Q: Exit

OK ~ ~ above is the whole contents of this chapter ~ ~ ~ Although all are talking about the man help document, but this is very important! Very important (serious face)

It took so long to finally put the use of the order to help to talk about the problem after the students do not understand the order, to habitually use Help or Man command to obtain assistance OH ~ ~

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End the end

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The zero-based Linux seventh chapter