Why are square brackets proscribed characters in writing tag to filename?

Hi music friends,
This is a fine program, but I can't write my syntax without square brackets. Why are they disallowed in writing tag to filename?
My syntax is:
Syntax=Filenamevenueinfo[info]

example,
OneDollaBillLeft[live,1-15-14@JungleJam,DocelunasResort,Jaco,CostaRica](2014,ZachDeputy,AKAZachry Deputy,Bluffton,SC)

Also, I read all the help file thoroughly but haven't figured out how to search and replace characters in only one column. Any suggestions would be appreciated. Thanks Tom Z, windking@gmail.com

The square brackets serve to enclose optional parts of a filename (very useful as it shortens otherwise lengthy $IF() statements).
To get the bracket, use them with apostrophes around them : '[' and ']' - then they are taken as literals

This is the help on "replace":

You can't select "this column only" in Mp3tag to search & replace content. You always choose one or more songs.

If you want to search and replace one specific tag in multiple files you can do it by
a) adding this field to the tag panel and adjust it for the selected songs
or
b) create a new replace action for this tag and replace the content of the given tag

Thanks very much; this is a very fine program, especially now that I don't have to graft the brackets to the title field manually!

Thanks much. I've used ID3TagIt for many years, which had an excellent search/replace feature.

MP3tag HAS an excellent search/replace function - you find it (as a one off) in Actions(quick).
The advantage of this concept is that you can use such an action as part of a more complicated batch job, an action group.
Searching in MP3tag usually means "filtering".