Tag Archives: Command line

Taking control of your command line history

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Thanks to Kean Walmsley’s post on his Through the Interface blog, I have learned something that would have been handy to know for the last decade or so, but which somehow escaped my knowledge. I learned how to increase the size of AutoCAD’s command line history cache. It defaults to 400 lines, which isn’t enough for me. I think this information deserves a wider audience than the ubergeek developers who frequent Kean’s blog, so here goes.

Although it’s not directly mentioned on Kean’s post, you can find the current command line history cache length setting like this:

(getenv "CmdHistLines")

This will return a value showing the number of command lines AutoCAD remembers, e.g. “400”. Although this is used as an integer value, it is passed to and from the Registry as a string. You can set a new value as shown below. Again, use a string, and note that values outside the range 25 to 2048 will be ignored:

(setenv "CmdHistLines" "2048")

Also, if you don’t like AutoCAD repeatedly stopping during a long listing (e.g. SETVAR ? *), you can turn off that feature by setting the QAFLAGS system variable to 2. Don’t set it to 8191 as suggested in Kean’s post, because that will change a lot of other settings, few of which are documented publicly.

Can you work without a command line?

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On the Project Butterfly blog, a recent poll gave these choices:

  • I can’t work without the command line
  • I think it’s time for a new way to draw without the command line

In a follow-up post, the observation was made that “We thought that only a few people would work without a command line, but the results were refreshing.” Apparently, only 66% of respondents selected the first of the available options.

To this I respond, “Beware the trap of the biased sample”. The poll asked people who are largely users of a product that involves drawing without a command line if they can work without it. In response, an amazing 2/3 of them say “I can’t work without the command line”, i.e. they can’t possibly do what they are currently doing, every time they use the product on which the blog is based.

How is that “refreshing”? 34% is an incredibly small number when the only alternative answer is self-contradictory. It should be very close to 100%, surely?

Every poll has a biased sample, including my own polls here. The trick is in working out how strong the bias is and determining if it invalidates the results. In this case, readers of the Butterfly blog are largely users of a command-line-less product and therefore likely to have a strong bias against the command line. So that 66% number would be a bit bigger if addressed to a more general population, I reckon.

I’ve added my own poll for my own biased sample (that’s you lot out there, largely users of a command line-based application) using exactly the same question format. I’m not entirely happy with the way the options are worded as it is not entirely neutral, but I’ll stick with it for the purpose of the comparison.

While I might dispute the conclusions that might be drawn from the poll, I must say that I like the way the Project Butterfly team is doing this in the open. It’s much better than the traditional Autodesk practice of claiming that what they are doing is supported by polls among customers, then refusing all requests for the full details of those polls. As the devil is in the details, I automatically discount any such claims based on secret research, from Autodesk or anyone else. I encourage the Butterfly people to keep doing what they are doing, regardless of any nitpicking from me; it is very refreshing (there’s that word again) to see Autodesk being open and I want to encourage it.

In addition to voting, I’d love to have you add your own comments either for or against use of the command line in CAD. It may be old and unfashionable, but does that make it inefficient? Have you tried turning it off in AutoCAD and running purely on Dynamic Input? Have you had experience with CAD or similar products without command lines? Let’s hear it.