一直以来都是用adb install xxx.apk来安装Android的package，然后在模拟器的menu screen上点击执行程序，今天需要在命令行中执行Android程序，查了半天，终于找到了相应的指令：
首先我们看看am指令介绍吧：
# am usage: am [subcommand] [options] start an Activity: am start [-D] [-W] <INTENT> -D: enable debugging -W: wait for launch to complete start a Service: am startservice <INTENT> send a broadcast Intent: am broadcast <INTENT> start an Instrumentation: am instrument [flags] <COMPONENT> -r: print raw results (otherwise decode REPORT_KEY_STREAMRESULT) -e <NAME> <VALUE>: set argument <NAME> to <VALUE> -p <FILE>: write profiling data to <FILE> -w: wait for instrumentation to finish before returning start profiling: am profile <PROCESS> start <FILE> stop profiling: am profile <PROCESS> stop <INTENT> specifications include these flags: [-a <ACTION>] [-d <DATA_URI>] [-t <MIME_TYPE>] [-c <CATEGORY> [-c <CATEGORY>] ...] [-e|--es <EXTRA_KEY> <EXTRA_STRING_VALUE> ...] [--esn <EXTRA_KEY> ...] [--ez <EXTRA_KEY> <EXTRA_BOOLEAN_VALUE> ...] [-e|--ei <EXTRA_KEY> <EXTRA_INT_VALUE> ...] [-n <COMPONENT>] [-f <FLAGS>] [--grant-read-uri-permission] [--grant-write-uri-permission] [--debug-log-resolution] [--activity-brought-to-front] [--activity-clear-top] [--activity-clear-when-task-reset] [--activity-exclude-from-recents] [--activity-launched-from-history] [--activity-multiple-task] [--activity-no-animation] [--activity-no-history] [--activity-no-user-action] [--activity-previous-is-top] [--activity-reorder-to-front] [--activity-reset-task-if-needed] [--activity-single-top] [--receiver-registered-only] [--receiver-replace-pending] [<URI>]从上可知：
am start 用来启动一个activity
am startservice 用来启动一个service，比如我们要
am broadcast 用来发送一个广播
当我们要运行camera程序时，可以用以下命令：
# am start -n com.android.camera/com.android.camera.Camera