Is there a way to use bash to remove the last four columns for some input CSV file? The last four columns can have fields that vary in length from line to line so it is not sufficient to just delete a certain number of characters from the end of each row.
Cut can do this if all lines have the same number of fields or awk if you don't.
cut -d, -f1-6 # assuming 10 fields
Will print out the first 6 fields if you want to control the output seperater use --output-delimiter=string
awk -F , -v OFS=, '{ for (i=1;i<=NF-4;i++){ printf $i, }; printf "\n"}'
Loops over fields up to th number of fields -4 and prints them out.