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Here is the source to the 'lid' utility in my distribution. If you change the read to a write, and change the port/bit appropriately, it's pretty simple to change the LED output state.

---

/* quick & dirty check of whether the lid-closed button is pressed */
 
/* Adam Tilghman, 5/2005, released into the public domain */
 
#include <unistd.h>
#define CLPS7111_VIRT_BASE      0xff000000
#define PBDR 0x0001
 
int main(int argc, char **argv)
{
        unsigned char c = *(unsigned char *) ( CLPS7111_VIRT_BASE + PBDR );
 
        if (c & 0x08 ) {  /* lid switch is connected to PB bit four */
                return 1;  /* closed */
        } else {
                return 0;
        }
}