Cut a regex matching line and paste it at another line

Question

I am trying to edit a json file, and I need to take out the lines starting and ending with {% and %} respectively and move them to the beginning of the file. I need to do it at different places in a single file and repeat it for a lot of files, hence I am looking for a single command to this for one place and then I can repeat it again and again.

Ex. Current file:

{% data 1 %}

{

  "data1": [

     detail1a: data detail 1a

     detail1b: data detail 1b

  ]

}

{% data 2a %}

{% data 2b %}

{

  "data2": [

     detail2a: data detail 2a

     detail2b: data detail 2b

  ]

}

{% data 3a %}

{

  "data3": [

     detail3a: data detail 3a

  ]

}

In this file, i want to remove all the data xa/xb lines and paste them at the beginning of the file like:

{% data 1 %}

{% data 2a %}

{% data 2b %}

{% data 3a %}
<rest of the lines>% data 3a %}

Then I can use :%s/^\(\s\+\)]\n}\n{$/\1],/g to remove the }{ to join it as a single execution.

I can do /^{%.*%}$ to get the line but how do I cut it and move it to line 0 (pushing down whatever is at line 0 already).

Any help appreciated.

PS: This is my first post in stackechange and I tried looking for all the existing posts to my best. The closet I found is this (Cut line, trim it and then paste it on another line) but it doesn't solve my purpose. Please excuse if I missed some norms.

Answer 1

The most direct solution is a :global command:

:g/^{%.*%}$/m0

The slight problem is that this leaves the lines in reverse order. A simple solution is just to run it again! (By pressing :UpEnter.)

If that seems inelegant to you, it's also possible to do it in a single pass. Here's one way:

:2mark a
:2,$g/^{%.*%}$/normal! dd'aP

Noting that the first line is already in the correct place, we first set a mark a on the second line. We then run a :normal command on each of the remaining matching lines to move each of them above the line we just marked.

For more details, see:

• :help :global
• :help :move
• :help :normal
• :help cmdline-ranges