Eu faria o seguinte:
file="$1"
cat $file | awk 'BEGIN{FS=OFS=","} NF!=5{print "not enough fields"; exit} NR == 1 && ($1 != "nasme" || $2 != "designation" || $3 != "email" || $4 != "phone" || $5 != "group") {print "Wrong file headers"; exit}' > someoutputfile