While it is true that there are 18 fields in the heading line in file1, there are a lot more fields on subsequent lines in that file. The cut command you suggested would copy the input file to its output and add 16 trailing <tab> characters to each input line. Using awk to delete field $18 (assuming we set the awk field delimiter to four <space> characters would seem to be a request to delete the header line completely ($otherinfo expanding to $0 unless otherinfo is defined to be some numeric value) and to remove the first field on your other sample lines (since field 18 on the other lines is in file1 is 1).

And you haven't said how you "match" 17 fields from file1 (after removing the last 13 fields) with lines from file2 containing 10 fields. Do you match lines from file1 (after skipping line1) with lines from file2 (after skipping lines that start with a "#") sequentially? Do you match lines with identical field 2 values in both files? Or, is there some other criteria used to determine a match?

From the sample input and output you provided, I would guess that you are trying to:Is that an accurate statement of your requirements?