how to read axis ticks from file

If you set ytick=data,xtick=data, the ticks will be placed at the y- and x-values used in the first \addplot. And with extra y ticks={0,0.05,...,0.35} you get the default ticks as well. (Of course with different data, you have to change the values. The two numbers before ... is the first two values in the list, and the step is the difference between them. The list stops at the number after ....)

The filecontents stuff is only used to make the example self-contained, you don't need it for your own use, as you already have the hist1.data file.

The yticklabel style is used to get 0.06 instead of 6\cdot10^{-2} as the ticklabel.

\documentclass{report} \usepackage{pgfplots} % for histograms \usepackage{filecontents} \begin{filecontents*}{hist1.data} 1 0.06 3 0.23 5 0.35 7 0.2 9 0.1 11 0.04 13 0.01 15 0 17 0 19 0.01 21 0 \end{filecontents*} \begin{document} \begin{tikzpicture} \begin{axis}[ height = 0.4\paperheight, width = 0.7\paperwidth, extra y ticks={0,0.05,...,0.35}, ytick=data,xtick=data, yticklabel style={ /pgf/number format/fixed, /pgf/number format/precision=2, } ] \addplot [ybar interval, color = black, fill = blue, line width = 0.5mm] table {hist1.data}; \end{axis} \end{tikzpicture} \end{document}