How to re-format a .txt list in Applescript - macos

Question

I have a file (list.txt) with a list that contains thousands of lines that look like this:
carpet-redandblue
shelf-brown
metaldesk-none
Is there a script I can use to remove everything after the "-", including the "-" as well?
This is what I have so far:
set theFile to "/Users/home/Desktop/list.txt"
if theFile contains "-" then
set eol to "-"
else
set eol to "-"
end if
But doesn't seem to be working.
Do I have to define an output file with a filename and path?

Answer 1

This should do what you need, at least as I understand it. The script reads the text file into a variable. It then breaks the text into paragraphs (or lines) and splits each line at the first dash. It then converts each line back into paragraphs of a text. Finally, it writes the resulting text to a text file. If you prefer to use the resulting text in some other way, it is stored in the prunedText variable.
use scripting additions
(*
set rawText to "carpet-redandblue
shelf-brown
metaldesk-none"
*)
set rawText to read file ((path to desktop as text) & "list.txt")
set AppleScript's text item delimiters to "-"
set paraText to paragraphs of rawText
--> {"carpet-redandblue", "shelf-brown", "metaldesk-none"}
set wordPara to {}
repeat with eachLine in paraText
set end of wordPara to first text item of eachLine
end repeat
--> {"carpet", "shelf", "metaldesk"}
set AppleScript's text item delimiters to linefeed
set prunedText to wordPara as text
(*
"carpet
shelf
metaldesk"
*)
-- optionally
tell application "Finder"
set nl to ((path to desktop as text) & "newList.txt") as «class furl»
end tell
close access (open for access nl)
write prunedText to nl as text

Answer 2

This in my opinion is the easiest solution.
Open Terminal.app
Go to Finder and while holding the ⌘ key, drag and drop the folder containing your "list.txt" file directly into a Terminal window. This will change your current working directory in Terminal to the folder containing your "list.txt" file.
Then paste this following code into that Terminal window and press the Return key...
grep -E -o "^\w*" list.txt > new_list.txt
This will create a new file called "new_list.txt" with the hyphens and everything after them removed from each line of your original list.txt