gistfile1.js

function readLines(file_path,fn){
    var px=system.posix, 
        fd, s, i, len, 
        NL='\n',
        ES="",
        BS=8096,
        unused=[],
        trail_nl,
        lines,
        last_i;
    fd = px.fopen(file_path,"r");
    try{
        while((s=px.fread(1,BS,fd)).length>0){
            trail_nl=s.charAt(s.length-1)==NL;
            lines=s.split(NL);
            if(trail_nl){ 
                //when splitting with a trailing newline an "extra line" is added so discard it 
                lines.pop();
            }
            len=lines.length;
            if(len==1&&!trail_nl){
                unused.push(lines[0]);
            }else{
                last_i=len-1;
                if(unused.length>0){
                    lines[0]=unused.join(ES)+lines[0];
                    unused=[];
                }
                for(i=0;i<len;i++){
                    if(i<last_i||trail_nl){
                        fn(lines[i]);
                    }else{
                        unused.push(lines[i]);
                    }
                }
            }
        }
        if(unused.length>0){
            fn(unused.join(ES));
        }
    }finally{
        px.fclose(fd);
    }
}

var total=0,space=' ';

readLines("/dev/stdin", 
    function(line){
        var a=line.split(space), i, len;
        for(i=0,len=a.length;i<len;i++){
            total+=(parseInt(a[i],10));
        }
    });

print(total);