ref: c111d2942f6d2fe9fd53ee2fe681d1186d4550f7
dir: /rc/bin/uptime/
#!/bin/awk -f BEGIN{ getline sysname < "/dev/sysname"; getline < "/dev/time"; sec = sprintf("%d", $3/$4); ct = sprintf("%02d:%02d:%02d", sec%86400/3600, sec%86400%3600/60, sec%60); printf("%s up %d days, %s\n", sysname, sec/86400, ct); exit }