$read(c:\test.txt,ntw,*ball*) finds the first occurrence of the string 'ball' even if it's part of words like balloon or eyeball. If you want to find it only as a complete word, the problem with searching $read(c:\test.txt,ntw,* ball *) is that it won't find when ball is not preceded and followed by a space, as when it begins or ends the line. So you would be forced to do the first search like:
reading the line with:
var %line $read(c:\test.txt,ntw,*ball*)
then check to see if the line returns ball as a word token or was part of another word:
var %word $findtok(%line,ball,1,32)
if %line is blank, then the string 'ball' isn't in the file.
if %word is blank, then the string 'ball' was part of another word or was touching non-space delimiters like !.,? etc.
If you want to find 'ball' even if it touches commas, first change the punctuation to spaces before using findtok:
var %word $replace(%word,!,$chr(32),$chr(44),$chr(32),$chr(63),$chr(32),.,$chr(32))
If that line contained what you want to count as the 1st occurrence of 'ball', you increment your counter from 0 to 1.
$readn contains the line number last read using $read, so you can find the next line with 'ball' by starting to read at the next line:
var %line $read(c:\test.txt,ntw,*ball*, $calc(1+$readn) )
that last parameter is optional, and if not used it assumes start with line #1.
You then repeat the process of finding if that next line counts as 'ball', and if not keep repeating until you do find it or %line is blank because it reached the end of the file and found nothing.
If you want to find the Nth occurrence and N is a large number, you probably want to use /filter to grab all occurrences of *ball* to a @window to avoid N disk reads.
You can make your search much faster by doing some pre-processing of your text file to ensure that 'ball' is always preceded AND followed by a delimiter. Find a character that won't appear in your text file like the ^ symbol, then change all spaces into ^ and also make sure each line begins and ends with the ^ symbol. This way you can filter *^ball^* into a @custom window and know that line N of the @custom window will be the Nth occurrence of ball that you want.
