Which Regular Expression's engine are you recommend for Keyboard Maestro?

I start with Regular Expression how to run my file to ground.
Which Regular Expression's engine are you recommend for Keyboard Maestro ?
This time around, I check with Reggy.app using (Ruby, Perl)engin & MatchAll.
When I try to use Expressions.app or RegExRX or regex.app, sometimes
response variance are emerged from their resulting.

As the maxim goes " Better to ask the way than go astray."

Please give me your suggestions for improvements.
Thanks in advance.

Kindest regards,WAKAMATSU (boehmflute)

First of all, I made a master.tex and come down content-1.tex, content-2.tex, content-3.tex, ....etc. ,
In this master.tex using in parallel with simplest command as bellow :


Keyboard Maestro uses ICU Regular Expressions , which are very similar to PCRE - Perl Compatible Regular Expressions

The [ICU] regular expression patterns and behavior are based on Perl's regular expressions.

The macOS provides the ICU RegEx engine, so any app or script that uses that should be fully compatible with KM.

Personally, I use RegEx101.com the most for developing and testing RegEx. It is very rare to find a RegEx pattern there that is not compatible with KM. The only notable exception is that ICU (and therefore KM) does NOT support extended metadata in replacement patterns.

Just be sure to set the RegEx "Flavor" to "PCRE" in whatever tool you are using if the ICU flavor is not available.

I also use the Mac app RegExRX for some special cases.

For more info, see Using Regular Expressions in KM.

Dear JMicjaelTX,
Thanks a lot.
I will study more.
Currently I am studying Jeffrey Friedl: "Masterins Regular Expressions". I am still reading the first 60 pages.
Yours, WAKAMATSU (boehmflute)

Dear JMicaelTX,
May I ask you a question?
Is it supposed to use RegExRX in special cases?
In what circumstances will you use it?
I got an answer from this forum
RegEX search specification \ include \ {. +? . \ W {3} }
When I use this setting with RegExRX
\ include {content - 1}. tex
\ include {content - 2}. tex
\ include {content - 3}. tex
It will not be searched.
These comments come out as "Does not apply to search conditions"?
Is "avoidance" with a special character string "does not recognize" in RegExRX?
I have not tried searching on RegEx 101.com using the Internet,
Is there any other way?

Best regards, WAKAMATSU (boehmflute)

The only case that comes to mind is when I need to develop/test a RegEx that specifically looks for RETURN (\r) as a new line characters. We can't use RegEx101.com for this, or BBEdit, because RETURN characters are converted to LF (\n) when the text is pasted into the sample text area.

I don't understand what you are asking. It is best if you can use RegEx101.com because you can save your RegEx snippet and post the link here.

Dear JMicaelTX,
Thanks a lot.
Your explanation helps me how to use RegEX with specific applications.
RegExRX.app have used with this sentences.


It seems that my setting was bad.
In an example sentence
\documentclass {jarticle}
Without \begin {document}
There is no search target. I got a comment.
If it is the original wording (quoted sentence)
Without problems \inculede {content - 1.tex} etc etc
I searched for it.
I will attach both screenshots.
(With Documentclass and without it.)
Thank you for your consulting.
Best regards, WAKAMATSU (boehmflute)

I edited your post to put your data in Code Block:


Please always use a Code Block to show your data so that all special characters like TAB and SPACE are retained.

I'm still having a hard time understanding you.
It would greatly help if you would always:

  1. Show your real-world source text in a Code Block.
    • Include multiple examples if needed to cover all of your use cases.
  2. Show the desired results, also in a Code block.
  3. While I would prefer RegEx101.com, if you use RegExRX, please save the snippet file, and upload in a Zip file so that it is easy and clear for us to use.

Dear JMicaelTX,
Sorry for the inconvenience.
By the way, I still do not understand well what is "Code Block" mean.
Looking up from the "link" of your post, what does this mean? I will study it.
Is it a macro that can be used with LaTeX?
When using RegExRX.app, as you pointed out, I will send it as a Zip file from next time.
thx and regards, WAKAMATSU (boehmflute)

Dear JMicaelTX,
Sorry for the inconvenience.
Today afternoon, I retested RegEX search again with RegExRX.app.
Strangely, this time, it picked up 3 search results "\inculede{content-1.tex}" even if it had [\jarticle] at the beginning or not.
Please discard the report of the previous search result.
It is my own mistake that some inconvenience occurred.
I apologize again.
thx and regards, WAKAMATSU (boehmflute)

Did you read the Code Block link:

What part of that do you not understand?

Dear JMicaelTX,
Thank you for listening to me for any questions.
Just insert your text between the lines with the triple backquotes:

---Your CODE here

I have a difficulty to find backquote & using with my Japanese Keyboard.
I paste & copy it from My Keyboard.
Is this [`] correct in the form of letters?
The top backquart,those copied and pasted from your article.
Please tell me if there is any difference.
Now,should I write like this?

---Your CODE here

Is there any problem with the above method of filling out?
thx and regards, WAKAMATSU (boehmflute)

No, you did very well.

One minor change:
Instead of




for showing text that you want to process using RegEx.
I have changed you post to use this.