Use the Find Command:
(underlines “_” indicate spaces)

Find_/i_”mark”_c:rproclient.prn_>_c:maillist.prn

steps:
1. Mark customers witht he Mark Customer Ultility (might use a best seller by customers to help determine mark points by purchases)
2. Export customers to an ascii file, Client.prn
3. Use the DOS Find command to dissect the file and write only the marked records to the new file.

Dos Help text for FIND:
FIND [/V] [/C] [/N] [/I] “string” [[drive:][path]filename[ …]]

/V Displays all lines NOT containing the specified string.
/C Displays only the count of lines containing the string.
/N Displays line numbers with the displayed lines.
/I Ignores the case of characters when searching for the string.
“string” Specifies the text string to find.
[drive:][path]filename
Specifies a file or files to search.

If a pathname is not specified, FIND searches the text typed at the prompt
or piped from another command.