There is a para break at the end of my .csv file. I tried to remove the blank line that is at the end of the file using the following command.
sed -i \'/^$/d\' c
Try ${/^$/d;} this will only match an empty line if it is the last line of the file.
${/^$/d;}
Update: for your second question, just remove the 1 before the s, i.e.: sed -i 's/^[^0-9]*//' combined.csv
sed -i 's/^[^0-9]*//' combined.csv