Open the SVG document in a Web document editor (a UTF-8 text editor that saves files with Unix line endings.)

You will see an *svg* tag that has width, height, and viewBox attributes:

    <svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0" y="0" width="960" height="540" viewBox="0, 0, 960, 540">

… those are the attributes you want to change to change how your SVG document displays in a browser. You can find lots of documentation of these attributes and how they affect the display of an SVG.

You can change these attributes in a batch way by doing a multiple-file find and replace of your SVG documents in the same way you would do a find and replace across multiple HTML documents in almost any Web document editor.

If you are tracing your bitmap images in Inkscape, it may be the case that the trace tool in Inkscape works in a batch fashion from bash. If not, you may be able to get a standalone version of that tracing tool that does, or another tracing tool that does.

Something to consider, though, is looking for native SVG replacements for these icons. There are a lot of free and low-price stock SVG icons for Web pages. The quality of their SVG formatting will likely be better than your traced output. If you take a natively-drawn SVG and convert to PNG and then trace that PNG to SVG and compare those 2 SVG files, the natively-drawn SVG might be 1/10th the size. That means not only 1/10th the download speed but also 1/10th the rendering speed. For icons you might be using on every page, that can be a significant difference.