# set a variable to know if a file is the first one
# because we don't want to skip the head line from the first file
first=1
# for each of *.csv file names, assign it to i
for i in *.csv; do
  # if you repeat this script, we don't want to merge
  # the previously merged file again
  if [ "$i" = "merged.csv" ]; then
    # skip this file
    continue
  fi
  # if this file is first
  if [ $first -eq 1 ]; then
    # print everything
    cat "$i"
    # subsequent files won't be first anymore
    first=0
  else
    # for non-first files, skip the first line
    tail -n +2 "$i"
  fi
done > merged.csv # forward any outputs from the above for loop
                  # to merged.csv