I was able to modify an example I had on my site fairly easily and came up with this script that seems to work fine:
proc main
string sLine1 ;Line of data read from file 1
string sLine2 ;Line of data read from file 2
integer iLen ;Holds length of sLine2
long lLen ;Long variable used in disk operations
if fopen 0 "file1.txt" READ ;If file 1 is opened successfully
if fopen 1 "file2.txt" READWRITE ;If file 2 is opened successfully
while not feof 0 ;While data exists in file 1...
fgets 0 sLine1 ;Read line from file 1
while not feof 1 ;While data exists in file 2...
fgets 1 sLine2 ;Read line from file 2
if strcmp sLine1 sLine2 ;If lines are identical
strlen sLine2 iLen ;Get length of line
lLen = iLen ;Save in long variable for use in disk operations
fseek 1 (-lLen) 1 ;Back up file pointer by length of current line
fdelblock 1 iLen ;Delete current line from file 2
ftell 1 lLen ;Get current file pointer
fclose 1 ;Close file 2
fopen 1 "file2.txt" READWRITE ;Reopen file so we can continue checking the remainder
fseek 1 lLen 0 ;Set file pointer to previously-read location
endif
endwhile
fclose 1 ;Close file 2
fopen 1 "file2.txt" READWRITE ;Reopen for next pass through file 2
endwhile
endif
endif
fclose 0
fclose 1
endproc
aspect@aspectscripting.com