Android :: Adb Controls G1 Keyboard LEDs

At the moment the LEDs that light up the keyboard of the G1 (HTC Dream) are very quick to turn off, I time it at six seconds. This is a pain when using the phone in the dark as you must press a button in order to turn the lights back on if you look away even for a very short time. Since my G1 is rooted I have access to the system files and when using adb to open a shell (adb shell) to the USB connected phone I can set the brightness file to a positive value using echo 1 > /sys/class/leds/keyboard-backlight/brightness. This keeps the keyboard on, until the screen is set to turn off (two minutes on my phone). When I attempt the same using a Terminal Emulator or writing a simple app which should execute the same it does nothing despite both having root access. Why is this?