Merging Multiple CSV Files without merging the header
You'll need more than the cat command, as described here:

Say you have 3 CSV-files: file1.csv, file2.csv, and file3.csv and want to join them to bigfile.csv and your header is always (only) the first line, then use 

either (keep header from first file "file1.csv"):

cat file1.csv &lt;(tail +2 file2.csv) &lt;(tail +2 file3.csv) &gt; bigfile.csv


or (remove header from all files who's names begin with "file"):

awk 'FNR &gt; 1' file*.csv &gt; bigfile.csv