What useful Android Shell commands do you know? There are questions pertaining to the use of the Android Shell or to finding a documentation of the Shell commands on Android. Since I haven't found anything convenient, I would like to use this thread to compile a list of "useful" Android commands. I am going to add commands as they are posted.
App Management

Use Android package manager pm

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]


Examples

Install the package com.twitter.android-1.apk from the SD card

pm install /sdcard/com.twitter.android-1.apk


List installed packages that contain the term twitter

pm list packages | grep twitter


Show the install directory of the twitter package

pm path com.twitter.android


Processes

top


Lists all running processes / apps with live updates showing CPU usage, PID,...

ps


Lists all running processes / apps and allows filtering using grep

Examples

ps | grep apps


Lists all running apps on your phone

Mounting

mount -o rw,remount -t "filesystem" "Device" "Mount Point"


Allows you to remount your partitions for write access or to mount images.

Examples

Write access for the root filesystem

mount -o rw,remount -t rootfs /


Write access for your /system partition

mount -o rw,remount -t yaffs2 /dev/block/mtdblock4 /system


Write access for /system using busybox

busybox mount -o remount,rw /system


Mount the contents of myimage.img, viewable in the folder myimage

mount -o loop /sdcard/myimage.img myimage


Other

getprop can show interesting details from the device configuration, such as DNS servers, gateways, GSM details, running services, build parameters, version info etc.