Please note than I’m using CyanogenMod 7.

First of all you have to know the Intent and Activity of your interest.

The best way to find them I found is to use logcat.

Open a shell

adb shell

Start logcat filtering the needed rows:

logcat | grep 'Starting:'

Start the app you want to launch later in the standard way (use your phone launcher icon).

Take a look to the lines which come from logcat (i.e. launching Shazam):

I/ActivityManager( 205): Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 pkg=com.shazam.encore.androidd cmp=com.shazam.encore.android/com.shazam.android.Splash bnds=[365,244][475,362] } from pid 305 I/ActivityManager( 205): Starting: Intent { act=android.intent.action.VIEW flg=0x4000000 cmp=com.shazam.encore.android/com.shazam.android.Home (has extras) } from pid 8096

Now start the app via am:

localhost / # am start -a android.intent.action.MAIN -n com.shazam.encore.android/com.shazam.android.Splash

Look at your phone.

Now you can combine all in one single command:

adb shell 'am start -a android.intent.action.MAIN -n com.shazam.encore.android/com.shazam.android.Splash'

Done.