Configure the mongo Shell-官方文档摘录

Posted 2020-09-28 熊出陌

Customize the Prompt 自定义提示

You may modify the content of the prompt by setting the variable prompt in the mongo shell. The prompt variable can hold strings as well as javascript code. If prompt holds a function that returns a string, mongocan display dynamic information in each prompt.

You can add the logic for the prompt in the .mongorc.js file to set the prompt each time you start up themongo shell.

大概的意思:你可以通过修改mongorc.js这个文件来让你的终端提示符变得不太一样

 注意：

# vim /root/.mongorc.js

如果使用yum 装的，这个文件在/root/目录下

 

Customize Prompt to Display Number of Operations

For example,to create a mongo shell prompt with the number of operations issued in the current session, define the following variables in the mongo shell:

cmdCount = 1;
prompt = function() {
             return (cmdCount++) + "> ";
         }

The prompt would then resemble the following:

1>
2>
3>

Customize Prompt to Display Database and Hostname

To create a mongo shell prompt in the form of <database>@<hostname>$, define the following variables:

host = db.serverStatus().host;

prompt = function() {
             return db+"@"+host+"$ ";
         }

The prompt would then resemble the following:

[email protected]$

Customize Prompt to Display Up Time and Document Count

To create a mongo shell prompt that contains the system up time and the number of documents in the current database, define the following prompt variable in the mongo shell:

prompt = function() {
           return "Uptime:"+db.serverStatus().uptime+" Documents:"+db.stats().objects+" > ";
         }

The prompt would then resemble the following:

Uptime:5897 Documents:6 >

Use an External Editor in the mongo Shell

You can use your own editor in the mongo shell by setting the EDITOR environment variable before starting the mongo shell.

export EDITOR=vim
mongo

Once in the mongo shell, you can edit with the specified editor by typing edit <variable> or edit<function>, as in the following example:

1. Define a function myFunction:

   function myFunction () { }
   

2. Edit the function using your editor:

   edit myFunction
   

   The command should open the vim edit session. When finished with the edits, save and exit vim edit session.

3. In the mongo shell, type myFunction to see the function definition:

   myFunction
   

   The result should be the changes from your saved edit:

   function myFunction() {
       print("This was edited");
   }
   

NOTE

As mongo shell interprets code edited in an external editor, it may modify code in functions, depending on the JavaScript compiler. For mongo may convert 1+1 to 2 or remove comments. The actual changes affect only the appearance of the code and will vary based on the version of JavaScript used but will not affect the semantics of the code.

以上大概的意思是:通过集中方式来设置显示的方式，需要注意的是mong shell的解释器会依赖于js的版本，即使你使用了编辑器，还是依靠于js的解释器。它只会影响代码的展现而不会影响代码本身的意思

Change the mongo Shell Batch Size

The db.collection.find() method is the JavaScript method to retrieve documents from a collection. Thedb.collection.find() method returns a cursor to the results; however, in the mongo shell, if the returned cursor is not assigned to a variable using the var keyword, then the cursor is automatically iterated up to 20 times to print up to the first 20 documents that match the query. The mongo shell will prompt Typeit to iterate another 20 times.

You can set the DBQuery.shellBatchSize attribute to change the number of documents from the default value of 20, as in the following example which sets it to 10:

DBQuery.shellBatchSize = 10;
大概的意思是:因为在mongo shell中，默认只会将前面20条的结果显示出来，修改默认的显示迭代次数，可以使用

DBQuery.shellBatchSize来设置