Every time I use emacs, it automatically saves a backup file which filename ends with "~". From time to time, I issue a recursive find command to wipe out (delete) every emacs backup file from my home folder. find . -iname \*~ -exec rm -rfv {} \; And everything is clean. I do it strictly to clean things up... not for any disk space concern... But I was wondering how much disk space those backup files are consuming... So, instead of an rm command, I had executed a df and piped all to awk to summarize... find . -iname \*~ -exec du -s {} \; | cut -f 1 | awk '{s+=$1} END {print s}' This time all the emacs backup files were consuming only 1.6M, which isn't big deal... but I think it is better to get rid of them.