Some important facts about file names

It is worth remembering that:

• File names in Linux, just like command and option names, are case sensitive. The names File.txt and file.txt refer to different files.

• File names beginning with a period (“.”) character are 'hidden', so if you type ls you won’t see them unless you also use the option -a. Some applications usually place their configuration/settings files in your home directory as hidden files (if you try ls -a ~ you may see there are quite a lot of them.)

• Linux supports file names containing white spaces and punctuation characters, so you might be tempting to start writing Long, Complicated Filename That Look Like This!!!. However, these filenames are often hard to interact with in other commands later, so for bioinformatics work it is generally best to restrict to a few characters - letters, numbers, the period (“.”), dash (“-”), and underscore (“_”) are generally good - and to try to avoid using spaces. You will thank yourself later for this!

• You should probably avoid using bash command names as filenames: although possible, this might mess up your commands.

## Next steps

Next we will learn more about working with files.