Eliminate a loop

```
$ time ./loop-echo-hr >/dev/null # 100000 chars wide

real	0m2.142s
user	0m2.082s
sys	0m0.055s

$ time ./printf-tr-hr >/dev/null # 100000 chars wide

real	0m0.022s
user	0m0.018s
sys	0m0.005s
```