在看相关PackageManager代码时，无意中发现Android 下提供一个pm命令，通常放在/system/bin/下。这个命令与Package有关，且非常实用。所以研究之。
0. Usage：
usage: pm [list|path|install|uninstall]
pm list packages [-f]
pm list permission-groups
pm list permissions [-g] [-f] [-d] [-u] [GROUP]
pm list instrumentation [-f] [TARGET-PACKAGE]
pm list features
pm path PACKAGE
pm install [-l] [-r] [-t] [-i INSTALLER_PACKAGE_NAME] [-s] [-f] PATH
pm uninstall [-k] PACKAGE
pm enable PACKAGE_OR_COMPONENT
pm disable PACKAGE_OR_COMPONENT
pm setInstallLocation [0/auto] [1/internal] [2/external]
The list packages command prints all packages. Options:
-f: see their associated file.
The list permission-groups command prints all known
permission groups.
The list permissions command prints all known
permissions, optionally only those in GROUP. Options:
-g: organize by group.
-f: print all information.
-s: short summary.
-d: only list dangerous permissions.
-u: list only the permissions users will see.
The list instrumentation command prints all instrumentations,
or only those that target a specified package. Options:
-f: see their associated file.
The list features command prints all features of the system.
The path command prints the path to the .apk of a package.
The install command installs a package to the system. Options:
-l: install the package with FORWARD_LOCK.
-r: reinstall an exisiting app, keeping its data.
-t: allow test .apks to be installed.
-i: specify the installer package name.
-s: install package on sdcard.
-f: install package on internal flash.
The uninstall command removes a package from the system. Options:
-k: keep the data and cache directories around.
after the package removal.
The enable and disable commands change the enabled state of
a given package or component (written as "package/class").
The getInstallLocation command gets the current install location
0 [auto]: Let system decide the best location
1 [internal]: Install on internal device storage
2 [external]: Install on external media
The setInstallLocation command changes the default install location
0 [auto]: Let system decide the best location
1 [internal]: Install on internal device storage
2 [external]: Install on external media
1. 具体使用方法：
1.1：察看已安装的包：
pm list package
此时则显示所有已经安装的包名。
pm list package -f
也显示associated文件所在目录(即保存的APK文件)
1.2：察看已知的权限组：
pm list permission-groups
1.3：察看所有已知的权限：
pm list permissions
1.4：列出所有硬件相关信息：
pm list features
结果通常类似：
feature:reqGlEsVersion=0x20000
feature:android.hardware.bluetooth
feature:android.hardware.camera
feature:android.hardware.location
feature:android.hardware.location.network
feature:android.hardware.microphone
feature:android.hardware.sensor.accelerometer
feature:android.hardware.sensor.compass
feature:android.hardware.touchscreen
feature:android.hardware.wifi
1.5：列出指定包名的 associated 文件 (APK存档文件) 所在：
例如：
pm path com.TDiJoy.fane
package:/mnt/asec/com.TDiJoy.fane-1/pkg.apk
1.6: 安装APK：
pm install [-l] [-r] [-t] [-i INSTALLER_PACKAGE_NAME] [-s] [-f] PATH
PATH 指 APK文件绝对路径和文件名。
例如：
pm install /data/3dijoy_fane.apk
这几个参数很有用：
-r: 安装一个已经安装的APK，保持其数据不变。
-i：指定安装的包名。(没试出来)
-s: 安装到SDCard上。
-f: 安装到内部Flash上。
1.6：卸载APK：
pm uninstall 包名。
例如：
pm uninstall com.TDiJoy.fane
1.7: 得到和设置缺省安装位置：
The getInstallLocation command gets the current install location
0 [auto]: Let system decide the best location
1 [internal]: Install on internal device storage
2 [external]: Install on external media
The setInstallLocation command changes the default install location
0 [auto]: Let system decide the best location
1 [internal]: Install on internal device storage
2 [external]: Install on external media
pm getInstallLocation
得到缺省的安装位置。
设置：
pm setInstallLocation <0|1|2>
0: 自动。
1：内部Flash。
2：扩展存储设备。
实例：如何在海信2.2 STB上将APK安装到U盘中：
首先尝试使用：
pm setInstallLocation 2
之后安装之，没有用。
后来做如下尝试：
在其它设置->存储设备->制定默认存储设备中选择U盘为默认存储设备。
# pm install -s xxxx.apk
就可以成功。