If you use Linux and write any form of documentation you should give serious consideration to learning to use LATEX.
One of the features of Linux distributions is that they include a wealth of tools and applications. One of the disadvantages is that you still need tutorials to learn to use these. That is one of the features of open software, you do not pay for the product but you do pay for the support. It is an excellent way of generating revenue sources for those with expertise.
One of the programs that you will find in most distributions is LATEX. Donald Knuth invented a typesetting (I say invented because there is much more to it than a simple application program) program called TEX which manages low-level page set-up and layout in a very precise and portable fashion. It uses 32-bit descriptors for many features allowing a phenomenal degree of precision and range of size for such things as type size and position. The downside of this is that it is quite cumbersome to use TEX in its raw form (think about how difficult it would be if the designer of a page layout had to write out the exact specifications for the printer) As TEX comes with a well designed macro language it is possible to provide a high-level overlay that hides most of this low-level complexity. The most successful of these high-level overlays was developed by Leslie Lamport during the middle 1980s. It is called LATEX. I guess that is derived from Lamport and TEX.
Learning to use LATEX is hampered by the need to set up the required software on your computer. In a busy life these start up costs (in time) often result in good tools being left on the shelf. However if you already have LATEX and an editor such as Emacs from your Linux distribution much of those costs go away. You have got the product (and a very powerful one) on your machine and it would be worth investing time to learn to use it. Of course, you could go back to the original User's Guide and Reference Manual by Leslie Lamport (and he deserves his royalties for all that he did to make TEX useable by mere mortals) but there is certainly an advantage in using an up-to-date book that relates directly to your installation.
If you use Linux and write any form of documentation you should give serious consideration to learning to use LATEX. This book will help you with that task.