linux系统下怎么修改path环境变量？

linux修改PATH环境变量四种方式:

Linux修改PATH环境变量的四种方式，每种方式有不同的权限。以添加mongodb server变量为列：

1.修改临时型的PATH

查看PATH：echo $PATH

修改方法一：export PATH=/usr/local/mongodb/bin:$PATH

//配置完后可以通过echo $PATH查看配置结果。

生效方法：立即生效

有效期限：临时改变，只能在当前的终端窗口中有效，当前窗口关闭后就会恢复原有的path配置。

用户局限：仅对当前用户

2.修改当前用户的PATH

通过修改.bashrc文件:vim ~/.bashrc

//在最后一行添上：export PATH=/usr/local/mongodb/bin:$PATH

生效方法：（有以下两种）

1、关闭当前终端窗口，重新打开一个新终端窗口就能生效

2、输入“source ~/.bashrc”命令，立即生效

有效期限：永久有效

用户局限：仅对当前用户

3.修改所有用户的PATH

通过修改profile文件:vim /etc/profile/export PATH

//找到设置PATH的行，添加：

export PATH=/usr/local/mongodb/bin:$PATH

生效方法：系统重启

有效期限：永久有效

用户局限：对所有用户

4.修改系统环境的PATH

通过修改environment文件:vim /etc/environment

在PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"中加入入“:/usr/local/mongodb/bin”

生效方法：系统重启

有效期限：永久有效

用户局限：对所有用户

27种用法格式 :

用法说明 ：

1、 pm list packages : prints all packages, optionally only those whose package name contains the text in FILTER. Options:

例子：列出系统中所有packages

2、 pm list permission-groups : prints all known permission groups.

例子：

3、 pm list permissions : prints all known permissions, optionally only those in GROUP. Options:

例子：列出系统所有许可

4、 pm list instrumentation : use to list all test packagesoptionally supply to list the test packages for a particular application. Options:

-f: list the .apk file for the test package.

5、 pm list features : prints all features of the system.

例子：列出所有手机特性

6、 pm list users : prints all users on the system.

例子：

7、 pm path : print the path to the .apk of the given PACKAGE.

例子：按包名查找apk文件所在路径

8、 pm dump : print system state associated with the given PACKAGE.

9、 pm install : installs a package to the system. Options:

例子：

10、 pm uninstall : removes a package from the system. Options:

-k: keep the data and cache directories around after package removal. 保留数据

例子：

11、 pm clear : deletes all data associated with a package..

例子：只删除数据

12、 pm enable, disable, disable-user, disable-until-used : these commands change the enabled state of a given package or component (written as "package/class").

13、 pm grant, revoke : these commands either grant or revoke permissions to applications. Only optional permissions the application has declared can be granted or revoked.

14、 pm get-install-location : returns the current install location.

15、 pm set-install-location : changes the default install location.

NOTE: this is only intended for debuggingusing this can cause applications to break and other undersireable behavior.

16、 pm trim-caches : trim cache files to reach the given free space.

17、 pm create-user : create a new user with the given USER_NAME, printing the new user identifier of the user. 创建新用户

18、 pm remove-user : remove the user with the given USER_IDENTIFIER, deleting all data associated with that user 。 按用户ID删除用户

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