How to convert line to line stroke or dotted line?

[ooker]

I have tried using

Code: Select all

convert line.png -fill white -stroke black -strockwidth 0 line_stroke.png

but noting changes. What should I do? Thank you.

[snibgo]

"-fill", "-stroke" and "-strokewidth" are settings for operations that follow. But you have no operations.

[ooker]

so what operation should I use?

[fmw42]

Best if you provide your input image and explain what it is you want to do with it. snibgo is saying that you have all settings and no operators to use those settings.