[SIC\]COMPUTE OutVar LINES FileName [/BLANK]
Count the number of lines in a formatted file. More precisely, it counts
the number of carriage returns (same as Linux shell "wc -l"). Be careful
of missing carriage return at the end of your files.
The option /BLANK can be used to ignore blank and comment (starting with
"!") lines, in the same way the command ACCEPT does.