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smudge 04-17-2018 07:55 AM

REQ: Replace the regex engine
I came to post a request for the keyword regex feature to support mode directives like case insensitive (?i) but when searching the forum for other regex related posts, in this reply by Support Rep Brenda, she mentioned that the regex engine used in SecureCRT is ECMAScript (aka Javascript) but she didn't say which version *1. Looking up the supported feature list shows that mode directives are not available at all in EMCA so there is no reason to bother you with that request :rolleyes:

In almost every post I found regarding regex, one common request was to support phrases instead of just keywords. The answer was always that due to performance issues, phrase matching was too slow so it is not available. I, like so many others, would LOVE to have this feature added!

So, my request to your developers is replace the EMCAScript engine with a better/faster regex engine.

A quick search of regex engine speed comparisons shows there are many engines that perform much better than EMCA.
One small benchmark page showed the Intel Hyperscan engine blowing away all the others, with Google's RE2 engine just behind. I'm sure either of these would be a huge improvement over EMCA.

Please have a developer take an afternoon trying out some other engines that has support for more features and better performance.

If you can't find one that works as fast as you are requiring, pick the fastest and then put in a disclaimer in the keyword configuration dialog window like "Using advanced/complicated regex rules may cause performance issues".
I'm sure I'm not the only user that would be willing to live with slightly slower text drawing in exchange for phrase matching and/or directive modes.

Thanks for your consideration.

P.S. For anyone learning RegEx, check out the online regex utility and tutorial, As you enter your regex rule, it breaks it down and describes each step of the engine logic. This is an amazing tool for not only learning regex but to see how well the rule performs. There are many different ways to create a rule and some can be tens if not hundreds of times slower than other rules. If you are stuck with a complicated rule, you can share it with others in the community forum or even live chat with a regex expert! In a situation like in SecureCRT and having multiple regex rules constantly processing the session output, optimization is very important.

*1 : If the EMCA engine code hasn't been updated since the regex feature was added to SecureCRT, that would mean v5.x which is 7+ years old. :eek:

bgagnon 04-17-2018 08:31 AM

Hi smudge,

I'm working on your feature requests (we may as well capture all of them), but please elaborate on this statement:


I came to post a request for the keyword regex feature to support mode directives like case insensitive...
There is a Match case checkbox in the Keyword List Properties dialog. Does that not provide the functionality you need?

bgagnon 04-17-2018 09:17 AM

Hi smudge,

I understand now.

I have added this thread to the following feature requests in our product enhancement database (the second and third are new ones):
  • Support substring and phrase matches in keyword highlighting (regex with spaces)
  • Keyword Highlighting: Support for case insensitive in regex (?i)
  • Investigate using new script engine for regular expression support (not ECMA)
Should a future release of SecureCRT include any of these features, notification will be posted here.

If you prefer direct email notification, send an email to and include "Feature Request - Forum Thread #13089" in the subject line or use this form from the support page of our website.

Trey 01-29-2019 10:18 AM


I was reading through all the posts about highlighting phrases. I saw the answer about performance issues with EMCA, and then found this post.

Is there any updates to this? Did you all get to investigate a new regex engine?


ekoranyi 01-29-2019 10:36 AM

Hi Trey,

SecureCRT does not yet support "key phrase" highlighting or patterns that include spaces.

I have recorded your interest in our database of feature requests so that the product director can evaluate it for possible inclusion in a future release.

Feature requests are typically prioritized based on a number of factors including, but not limited to, the number of requests and the amount of implementation work required.

If this functionality becomes available in a future version, we will be sure to let you know. If you would like to be notified directly please send an email to with "Feature Request Forum Post 13089" in the subject line.

Trey 01-29-2019 01:23 PM


I was referencing the Feature Request that @smudge was asking about. No need to create another one.

Do you know if this has been looked at, or on any road map?

ekoranyi 01-29-2019 02:01 PM

Hi Trey,

I added your contact information to the existing feature request to support spaces in keyword highlighting patterns.

I can't speak to if/when this feature may become available in SecureCRT, that is a decision that would be made by the product director.

Maureen 12-17-2019 06:06 PM

The ability to use spaces in keywords (including regular expressions) has been added to SecureCRT 8.7, which is currently in beta testing. It can be downloaded here:


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