BEGIN { localoffset = 7.0/24 } (! /^#/ ) { jday = $1 + localoffset day = (int)jday time = (jday - day) * 24 hour = (int)time fltmin = 60 * (time - hour) min = (int)fltmin sec = (int)(60 * (fltmin - min)) print jday day time hour fltmin min sec printf("%d %02d:%02d:%02d ", day, hour, min, sec) print $0 }