To split large CSV (Comma-Separated Values) file into smaller files in Linux/Ubuntu use the split command and required arguments.
split -d -l 10000 source.csv tempfile.part.
Here “10000” indicates that each new file contains 10000 records,you change it to any number you want to, the smaller files would have that number of records. The new files are created with numbers suffixed. For example in this case the file names are tempfile.part.oo.csv, tempfile.part.01.csv and so on.