I am running a code on a particular core and am monitoring the cache misses in that particular core every second when my code is running. I can redirect that output to a .txt file. I wanted to know if it is possible to redirect the output to a libreoffice excel file which will allow me to generate a graph easily.
You should output the data into csv or tsv formatted file.
Any spreadsheet software will be able to open that as long as you have the format correct.