Question

I often work with text files which have a variable amount of whitespaces as word separators (text processors like Word do this, to distribute fairly the whitespace amount due to different sizes of letters in certain fonts and they put this annoying variable amount of spaces even when saving as plain text).

I would like to automate the process of replacing these sequences of whitespaces that have variable length with single spaces. I suspect a regex could do it, but there are also whitespaces at the beginning of paragraphs (usually four of them, but not always), which I would want to let unchanged, so basically my regex should also not touch the leading whitespaces and this adds to the complexity.

I’m using vim, so a regex in the vim regex dialect would be very useful to me, if this is doable.

My current progress looks like this:

:%s/ \+/ /g

but it doesn’t work correctly.

I’m also considering to write a vim script that could parse text lines one by one, process each line char by char and skip the whitespaces after the first one, but I have a feeling this would be overkill.

Answer 1

In the interests of pragmatism, I tend to just do it as a three-stage process:

:g/^    /s//XYZZYPARA/g
:g/ \+/s// /g
:g/^XYZZYPARA/s//    /g

I don’t doubt that there may be a better way (perhaps using macros or even a pure regex way) but I usually find this works when I’m in a hurry. Of course, if you have lines starting with XYZZYPARA, you may want to adjust the string 🙂

It’s good enough to turn:

    This is a new paragraph
spanning       two lines.
    And    so    is   this but on one line.

into:

    This is a new paragraph
spanning two lines. 
    And so is this but on one line.

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Aside: If you’re wondering why I use :g instead of :s, that’s just habit mostly. :g can do everything :s can and so much more. It’s actually a way to execute an arbitrary command on selected lines. The command to execute happens to be s in this case so there’s no real difference but, if you want to become a vi power user, you should look into :g at some point.