簡単です。基本的にはファイルを読み取り、結果をリストに入れます。次に、リスト番号を直接参照して、リスト内のアイテムを取得できます...
set filePath to (path to desktop as text) & "memberID.txt" -- path to the file
set idsText to read file filePath -- get the file text
set idsList to paragraphs of idsText -- turn the text into a list
set nextID to item 2 of idsList
または、繰り返しループでそれらすべてを取得できます...
set filePath to (path to desktop as text) & "memberID.txt" -- path to the file
set idsText to read file filePath -- get the file text
set idsList to paragraphs of idsText -- turn the text into a list
repeat with i from 1 to count of idsList
display dialog (item i of idsList)
end repeat