proj I-O
clear all

`Create a simple text file with three columns of data
me (report) test.dat
me 1 2 3
me 4 5 6
me 7 8 9
me (report) off

`Add a fourth line to the test.dat
write (lines) test.dat 10 11 12
view test.dat

`Begin commands to read data into variables.
variable n=0

Macro lines  `while loop that reads three variables from each line
 if eof then exit      `while not EOF do
 set n = {n} plus 1
 variable X{n}, Y{n}, Z{n}
 read X{n} Y{n} Z{n}
 exit lines            `exit vice execute avoids recursive macro error
/

`Read the first three values in each row into newly created variables
read (data) test.dat
.lines
read (data) off

`Write the variables to a txt file to verify.
write (variables) variables.txt
view variables.txt