Here are some caveats to watch out for when using wildcards. Since bash treats wildcard-related characters (?, [, ], *) specially, you need to take special care when typing in an argument to a command that contains these characters. For example, if you want to create a file that contains the string [fo]*, the following command may not do what you want:

$ echo [fo]* > /tmp/mynewfile.txt

If the pattern [fo]* matches any files in the current working directory, then you'll find the names of those files inside /tmp/mynewfile.txt rather than a literal [fo]* like you were expecting. The solution? Well, one approach is to surround your characters with single quotes, which tell bash to perform absolutely no wildcard expansion on them:

$ echo '[fo]*' > /tmp/mynewfile.txt