SWATCH Configuration: Dynamic Subject

[DUKEBD711]

I am monitoring a log with swatch and cannot figure out how to pull a number from the line I am watching for and insert it into the subject on an email.

For example:
Line = "I want to pull this number 123456 and put it in the subject of my email sent by swatch"

I have tried the below and other variations to no avail.

watchfor /I want to pull this number [0-9]{6} and put it in the subject of my email sent by swatch/
     exec echo $0 | mail -s "The number is " $7 email[at symbol]blah.com

watchfor /I want to pull this number [0-9]{6} and put it in the subject of my email sent by swatch/
     mail addresses=email[at symbol]blah.com,subject=The number is $7

Any help would be most appreciated, thanks.

[DUKEBD711]

It looks like I could use the 'pipe' command

pipe command[,keep_open]
Pipe matched lines into command. Use the keep_open option to force the pipe to stay open until a different pipe action is run or until swatch exits.

But I cannot get this to work ... I haven't found any examples online that work. Has anyone successfully used the pipe command?