Depends on the language and if you mean numbers recieved from the mud. Using an 'omit from output' trigger and script you can replace the line (sans any color information, which gets complicated to duplicate). As for inserting the commas:
VBScript:
FormatNumber(Expression [,NumDec[,IncLead[,UseParens[,Group]]])
In other words:
note FormatNumber("-0.4567",2,-1,-1,-1)
note FormatNumber("12245235",0,0,0,-1)
produces:
[-0.45]
12,245,235
NumDec = number of digits following the decimal.
IncLead = Show the '0' in cases where it is something like 0.1323
UseParens = show [] around negative numbers (common in spread sheets to see them easier).
Group = Add commas.
The IncLead, UseParens and Group settings are -1 = on, 0 = off, -2 = use default.
I am sure other languages have something like this as well, but not sure what they are. There are also some limitations to using omit from output and 'when' it displays. I believe the main one is that if you use 'send to script', then the commands to display text will be ignored. For example, if you have the following trigger and script:
<triggers>
<trigger
enabled="y"
match="test"
omit_from_output="y"
script="test22"
send_to="12"
sequence="100"
>
<send>note "test"</send>
</trigger>
</triggers>
------
script: set in Scripting->Scripts->Script File
------
sub test22(name, output, wildcards)
note "test 2"
end sub
When the word 'test' is recieved, you *won't* see the word 'test' repeated 'in' the trigger with 'send to script', but you *will* see 'test 2' appear when the same trigger calls the subroutine 'test22'. This is due to how Mushclient handles things in the 'send' field when using 'omit from output'.