'input-file' and 'output-file' vs. 'source-file' and 'target-file' as generic names

When documenting command-line things, it is often necessary to use generic names. Sometimes I use input and output words, and they play nice:

# example 1
pandoc input_file.md -o output_file.htm

But sometimes they don't play nice, and I use source and target instead:

# example 2
mv source_file.txt target_folder/

I have two questions here. The first question is whether it is fine (from the side of English language, which is a foreign one for me, logic, etc.) to use source and target pair only? Is it correct to say that this pair of words is more versatile then input and output? The second question is whether it is fine to use target when we don't use source? For example:

# example 3. ImageMagick will copy all the .jpg and .png files
# to target_folder, and then trim them there
magick mogrify -path target_folder/ -trim +repage *.(jpg|png)