Ons hernoem die onnodige duplikaatlêer.

Yes, ons means we in this sentence.

Afrikaans ons can also mean us, depending on its role in the sentence:

• Ons hernoem die lêer. = We rename the file.
• Hulle help ons. = They help us.

So, unlike English, the same word can serve both functions. Here it is the subject, so it means we.

In Afrikaans, verbs usually do not change according to the subject the way they do in English.

Compare:

• Ek hernoem = I rename
• Jy hernoem = you rename
• Ons hernoem = we rename
• Hulle hernoem = they rename

The verb stays hernoem in all these cases. This is one of the simpler parts of Afrikaans grammar.

Yes. Hernoem means rename.

It is built from:

• her- = re- / again
• noem = name / call

So hernoem literally means something like name again.

It works much like English rename:

• Ons hernoem die lêer. = We rename the file.

Here die is the definite article, meaning the.

So:

• die onnodige duplikaatlêer = the unnecessary duplicate file

A useful thing to know is that Afrikaans die does a lot of work:

• it is used for the
• it does not change for gender
• it is used for both singular and plural nouns in many cases

So Afrikaans is simpler than languages that have different forms for the depending on gender or number.

Because the adjective comes before the noun.

In Afrikaans, adjectives used before nouns often take an -e ending:

• onnodige duplikaatlêer = unnecessary duplicate file

Compare:

• Die lêer is onnodig. = The file is unnecessary.
  Here the adjective comes after is, so it is usually just onnodig.
• die onnodige lêer = the unnecessary file
  Here it comes before the noun, so it becomes onnodige.

This is a very common pattern in Afrikaans.

Afrikaans strongly prefers writing compound nouns as one word.

So:

• duplikaat = duplicate
• lêer = file
• duplikaatlêer = duplicate file

English often writes these as separate words, but Afrikaans usually joins them into a single compound noun.

This is very common:

• woordeboek = dictionary
• huiswerk = homework
• rekenaarskerm = computer screen

So duplikaatlêer is completely normal Afrikaans spelling.

The ë helps show how the word is pronounced and syllabified.

In lêer, the vowels are not simply merged into one sound. The spelling signals that the word is pronounced in separate parts, roughly like:

• lê-er

The little dots are called a diaeresis. In Afrikaans, they often show that vowels belong to separate syllables.

So duplikaatlêer should be read with lêer clearly pronounced as two syllabic parts, not as one blurred vowel sound.

Yes. This is normal main-clause word order:

Ons | hernoem | die onnodige duplikaatlêer
subject | verb | object

That is very similar to English: We | rename | the unnecessary duplicate file

Afrikaans main clauses usually put the finite verb in the second position, and in a simple sentence like this that gives you the familiar:

• subject
• verb
• object

You might be understood, but it is not the best equivalent for rename in this context.

Hernoem is the standard and most natural word for rename, especially in computer or file-related language.

• Ons hernoem die lêer. = natural for We rename the file
• Ons noem die lêer weer. would sound more like we name the file again, which is not as idiomatic

So for software, files, folders, and labels, hernoem is the better choice.

Afrikaans usually uses double negation.

So:

• Ons hernoem die onnodige duplikaatlêer. = We rename the unnecessary duplicate file.
• Ons hernoem nie die onnodige duplikaatlêer nie. = We do not rename the unnecessary duplicate file.

Notice the two nie words:

• one after the verb
• one at the end of the clause

That double nie ... nie pattern is a major feature of standard Afrikaans.