Do you know any editor for man(1) pages which work on text screen (terminal and console)? Searching the interned did not gave any useful results as the words are very common.
Or should I learn the details of the format and write it by hand?
You can write it e.g. in markdown
then convert it via e.g. pandoc
to manpage format ((t|g)roff
). Here is the fine manual: http://johnmacfarlane.net/pandoc/README.html .
HTH