I have previously posted how to compile git on Ubuntu but while using git I wanted to consulte the manual to get information about some commands and git help didn’t work. It seems that you have to manually specify when compiling that you want to have documentation included too.
Here’s how to do that. Go to the directory where you have unarchived git sources and type:
make doc sudo make install-doc
You can also combine them when you compile git:
make all doc sudo make install install-doc