Show current SHA1

Hi, hopefully a very simple newb question: "what is the command to report the current SHA1?" - explanation below.

I'm vc-ing my MSc thesis and associated code with git, it's working great for me. My supervisor requires regular submissions as editable Word docs so I publish my source HTML to him as RTF. He adds comments via Word & returns to me, I read in Open Office 3. This works, but there is often a week or more between him receiving the doc and returning it to me with comments.

I'd like to put the current SHA1 as text in the RTF so that I can generate a diff from my current version before responding to his comments.

The question then is: what is the command to report the current SHA1? Note I never branch in the HTML repo, it's entirely linear.

Many thanks, al.