No comma before independent clause?

Question

As I know, dependent clauses must be separated with a comma. Below are 2 sentences from the University of Leicester website. I don't understand why there are no commas where I expect them. Are these sentences just wrong or is it something specific to British English?

When including a number in a file name [no comma] always give it as a two-digit number rather than one, i.e. 01, 02 … 99, unless it is a year or another number with more than two digits.

If using a date in the file name [no comma] always state the date ‘back to front’, and use four digit years, two digit months and two digit days: YYYYMMDD or YYYYMM or YYYY or YYYY-YYYY.

Another sentence on the same topic, from the different website; again, the author speaks British English:

Long file names are more difficult to remember and recognise. Some words add length to a file name but do not contribute towards the meaning, for example words like “the”, “a”, and “and”. Where the remaining file name is still meaningful within the context of the file directory [no comma] these elements can be removed.

Or maybe these sentences are OK even in American English?

Answer 1

First, punctuation is not grammar. Punctuation does not exist in the spoken language. Punctuation is specified in "Style Guides," which differ in certain respects. Unless you know which Style Guide is used by the web authors for the University of Leicester, you cannot tell whether what you are seeing is mandated, permitted, or prohibited.

Second, your first two examples do not involve clauses but participial phrases, and your third example involves a subordinate rather than an independent clause.

Third, all your examples relate to computers. From long experience, I have found that many people who work with computers are willing to work hard at computer syntax but ignore best practices in English. Some seem to revel in writing bad English.

Fourth, I speak U.S. English, but I would certainly recommend commas in all three of your examples, whether we are talking about participial phrases or subordinate clause. My very limited experience with professional British writers has been that they would agree, but I admit that British English is frequently close to a foreign language for me. I frequently need sub-titles on British television shows.