extract-all-file-git-commits.sh

# this shell script extracts all prior versions of a file in a git repository
# make sure to enable execute permissions on this file if your operating system
#    requires it: chmod +x extract-all-file-git-commits.sh

# parameters:
# - path-to-file (from root of repository)
# - output directory
# - output file extention
# eg. ./extract-all-file-commits.sh "./public/data/vaccinations/locations.csv" "./output" "csv"

# smarter things it could do:
#   auto-detect extension from first parameter

#check to see if output directory exists; if not, make it
[ ! -d "$2" ] && mkdir -p "$2"

#generate the list of commits for the specified filespec and stick it in the temp directory
git log --pretty=format:"%H %cI" --reverse -- $1 > /tmp/extract-all-file-commits.txt

#iterate through the file in the temp folder and output the file from each commit with the timestamp as filename
while IFS=" " read -r item1 item2;
  do
    git show "$item1:$1" > "$2/$item2.$3";
  done < /tmp/extract-all-file-commits.txt