You can avoid having to run you script with bash middle.sh by giving the script the execute permission:
$ chmod a+x middle.sh
Recall from the file permission section that a+x means giving the execute permission to the user, group and others.
You will now be able to run you script on the command line with:
$ ./middle.sh
We usually call programs like Microsoft Word or LibreOffice Writer “text
editors”, but we need to be a bit more careful when it comes to
programming. By default, Microsoft Word uses .docx files to store not
only text, but also formatting information about fonts, headings, and so
on. This extra information isn’t stored as characters and doesn’t mean
anything to tools like head: they expect input files to contain
nothing but the letters, digits, and punctuation on a standard computer
keyboard. When editing programs, therefore, you must either use a plain
text editor, or be careful to save files as plain text.