There’s no specific functionality with MRtrix, but it’s a standard operation that many other packages will allow you to do, including MatLab, Excel, R, …

For instance, using free software on Linux, and assuming you’ve generated the histogram data file using e.g.:

```
$ mrhistogram image.mif data.txt -bins 100
```

You can plot that in R using:

```
$ R
...
> data <- t(read.csv("data.txt",comment.char="#",header=F))
> plot (data, type="l", xlab="intensity", ylab="count")
```

which produces something like:

Or in Octave:

```
$ octave
...
>> load data.txt;
>> plot (data(1,:),data(2,:),'k-');
>> xlabel 'intensity'
>> ylabel 'count'
```

Which looks much the same.

Or as a one-liner straight from the prompt using Octave:

```
octave --persist --eval "load data.txt; plot(data(1,:),data(2,:),'k-'); xlabel 'intensity'; ylabel 'count'"
```

(press Ctrl-D in terminal to close Octave & the figure and return to shell prompt)