"remount: not found" error I want to install an application as a system application.

To do so, I must remount the system partition RW, to do so I run the command adb shell remount rw in a terminal, but I get the error /system/bin/sh: remount: not found.

How can I remount the system partition RW?
The command is: adb remount. Please try this first however if it doesn't work, make sure your device is rooted, and try these commands:

adb shell
su
mount -o remount,rw /system

Those commands will directly remount the system as RW, however you must be rooted.