It is not possible in the generic case. In some special cases it is, e.g. for a PPP-type interface.
The workaround is to make a script that is scheduled at some interval, and keep the previous status in a global variable.
You script compares the current status with the previous status in the global variable, acts accordingly, and finally copies the current status to the variable before it exits.

I'm seeking a solution for CRS switch devices with RouterOS in Bridge Mode (I think the procedure could be the same on router devices).

Code: Select all

{
  :local f [:tobool [:len $gArr]]
  :if ($f = false) do={
    :global gArr [:toarray ""]
    :set ($gArr->"key1") "val1"
  }

  :put $gArr

}

You can print in /system script environment.

I gave two answers to two questions.

In environment all globals live. If not there then it is not a global.

Why do you need print while you have put and set?

For your script it is known that tobool is broken since a long time.

The print is a official command like put is. Print can do other stuff then put and they are used to their specific purpose.

Print is print and put is printing using put. Some things are just not straight forward.

What's new in 6.46beta44 (2019-Sep-19 05:54):

Changes in this release:

*) capsman - fixed channel auto reselection;
*) chr - added support for Azure guest agent;
*) console - fixed "tobool" conversion;

What's new in 6.46beta44 (2019-Sep-19 05:54):

Changes in this release:

*) capsman - fixed channel auto reselection;
*) chr - added support for Azure guest agent;
*) console - fixed "tobool" conversion;

As you noticed, it is not.

You initialize the variable inside a block, thus it's not visible outside.

@msatter, stop please. Your code can't be correct as you use $f in the initialization...

{
:if ([/system script environment find name="gArr"]) do={} else={:global gArr [:toarray ""]; :set ($gArr->"key1") "val2";};
}
{
:put [pick $gArr]
}

:if ([/system script environment find name="gArr"]) do={:put $gArr;} else={:global gArr [:toarray ""]; :set ($gArr->"key1") "val2";};
:if ([/system script environment find name="gArr"]) do={:put $gArr;} else={:global gArr [:toarray ""]; :set ($gArr->"key1") "val2";};
key1=val2

@msatter, stop please. Your code can't be correct as you use $f in the initialization...

My code is correct, as it runs in RouterOS. $f is local . You don't have always to go through the process of defining it. It not Cobol.

You initialize the variable inside a block, thus it's not visible outside.

But it's a global variable

• ... when used directly from command line (without block!) or...
• ... when initialized properly.

:global gArr;

{
  :global gArr;
  :if ([ :len $gArr ] = 0) do={
    :set gArr [:toarray ""];
    :set ($gArr->"key1") "val1";
  }
  :put $gArr;
}