The datamash one seems a good option, but even acknowledging that my answer may be overkill, just in case you want to do a bit more than just a mean, octave is not so verbose:

```
$ octave
octave:1> load timeMeasurements.txt
octave:2> mean(timeMeasurements)
ans = 2.6667
```

If you are doing means, remember that the same mean could come from very different behaviours, so the standard deviation is usually also relevant:

```
octave:3> std(timeMeasurements)
ans = 0.76376
```

or even a simple histogram is easy to do:

```
octave:4> hist(timeMeasurements)
```

Also, I think datamash is not in the apt-get repositories for trusty, only for newer versions.

### Edit:

Oneliner, for more script-friendly usages:

```
octave -q --eval "m = load(\"timeMeasurements.txt\"); mean(m)"
```