Fixed a command typo in the file I/O section

Before, we had:
```
    [10] $ valgrind ./myprogram 2>&1 > ALLthethings 
    [11] $ valgrind ./anotherprogram 2>&1 >> ALLthethings 
```
That doesn't actually work. Updated to:
```
    [10] $ valgrind ./myprogram > ALLthethings 2>&1 
    [11] $ valgrind ./anotherprogram >> ALLthethings 2>&1
```