title: How to split a huge .CSV file into n smaller files when an index in a particular column changes?
body: <p>I have been given five huge .CSV files that contain columns of data.  The files are so large that they don't even load completely in EXCEL.  I can load them if I open them in a text editor, however.</p>
  <p>I want to split each file into n smaller files according to an index in the first column.  For example, each file contains data for 50 locations.  Location 1 is called JEANNE in the first column.  So there are an arbitrary number (let's say &quot;m&quot;) of rows of data for JEANNE.  At row m+1, JEANNE changes to ALICE (for example) and there are l rows of data for ALICE, and so on for all the other sites.</p>
  <p>Does anyone know how I can do this in something like Awk without having to know the number of rows of data for each site in advance, but by using the change in index (e.g., JEANNE to ALICE)?  Thank you for any help.</p>