Nodejs file and file operations (read/write file deletion and rename)

Source: Internet
Author: User
Tags lstat

I learned about node. js most. I learned about the node. js file system today. Here I am looking for some file directory operation instances for node. js file systems. I will share them with you below.

Read/write files
Operations in nodejs are much easier! Let's take a look at several examples.


[Write a text file]
// Wfile. js
------------------------------

The Code is as follows: Copy code

Var fs = require ("fs ");

Var data = 'Hello dashboard ';
Fs. writeFile ('C: a.txt ', data, 'ascii', function (err ){
If (err ){
Console. log ('file writing failed ');
} Else {
Console. log ('Save successfully, hurry and check for garbled id ');
}
})


------------------------------
[Note: by default, the data encoding is utf8; mode = 438; flag = w]

 

[Read text files]
// Rfile. js
------------------------------

The Code is as follows: Copy code
Var fs = require ("fs ");

Var data = 'Hello dashboard ';
Fs. readFile ('C: a.txt ', 'ascii', function (err, data ){
If (err ){
Console. log ('file writing failed ');
} Else {
Console. log (data );
}
})

------------------------------
[NOTE: If no special encoding is available, binary data is returned as a buffer.]
[Note: Binary Buffer data printing result: <Buffer 68 65 6c 6c 6f 20 e8 97 5a a2>]

File directory operations


Nodejs file operations (fs)


When operating files, we need to require (load) the File System package to obtain the File operation function.

The Code is as follows: Copy code

Var fs = require ("fs ");


How to use this fs? In this case, we need to query the official API of nodejs.


Http://nodejs.org/api/fs.html

Basic file operations include creating, renaming, and deleting. Let's take a look at several examples.


[Create folder]

The Code is as follows: Copy code
// Newfolder. js
-----------------------------
// Load the file system module
Var fs = require ("fs ");

// Create a folder named a on drive C
Fs. mkdir ("c: a", function (err ){
If (! Err ){
Console. log ("operation successful! ");
} Else {
Console. log ("operation failed! ");
}
});

-----------------------------
[NOTE: If the folder contains err, an error message is displayed.]

Delete folder]

The Code is as follows: Copy code
// Removefolder. js
-----------------------------
Var fs = require ("fs ");

// Delete the folder in drive C
Fs. rmdir ("c: a", function (err ){
If (err ){
Console. log ("deletion failed! ");
} Else {
Console. log ("deleted successfully! ");
}
});

-----------------------------
[NOTE: If the deleted Folder does not exist, err will have an error message.]


[Rename a folder]
// Rename. js
-----------------------------

The Code is as follows: Copy code

Var fs = require ("fs ");

// Rename the folder to B
Fs. rename ("c: a", "C: B", function (err ){
If (err ){
Console. log ("Renaming failed! ");
} Else {
Console. log ("renamed successfully! ");
}
});

-----------------------------
[Note: The Folder does not exist, so err will have an error message.]


[Determine whether a file or folder exists]

The Code is as follows: Copy code

// Exsits. js
-----------------------------

Var fs = require ("fs ");

// Determine whether the folder exists
Fs. exists ("c: a", function (exists ){
If (exists ){
Console. log ("a folder exists ");
} Else {
Console. log ("folder a does not exist ")
}
});

-----------------------------
[Note: Then call the callback argument with either true or false
(The value of this callback function is true or false)]

[File type determination] [fs. stat (), fs. lstat () and fs. fstat ()]
// Stat. js
-----------------------------

The Code is as follows: Copy code
Var fs = require ("fs ");

// Obtain the type of the folder
Fs. stat ("C: a", function (err, stat ){
If (err ){
Console. log ("the file does not exist! ");
} Else {
Console. log ("file:" + stat. isFile ());
Console. log ("folder:" + stat. isDirectory ());
}
});

-----------------------------
[
Other status functions:

Stats. isFile ()
Stats. isDirectory ()
Stats. isBlockDevice ()
Stats. isCharacterDevice ()
Stats. isSymbolicLink () (only valid for fs. lstat)
Stats. isFIFO ()
Stats. isSocket ()]

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