I created this graph. The graph is shown correctly but I need the range on the y-axis to be from 10e-8 to 1. I would also like a grid. I'm a newbie with the pgfplots package.
\begin{figure}[htp]
\centering
\begin{tikzpicture}
\begin{semilogyaxis}[xlabel=distanza]
\addplot [domain=0.0000001:1,
thick,blue]
file {./MATLAB/file.txt};
\end{semilogyaxis}
\end{tikzpicture}
\end{figure}

width=13cm, as an option to thesemilogyaxisas in\begin{semilogyaxis[ymin=0.000000001,ymax=1,xlabel=distanza,grid=major,width=12cm]or globally, using something like\pgfplotsset{width=10cm}in the preamble. – Gonzalo Medina Dec 11 '12 at 23:30