Find oldest files in a git repo

find-old-files.sh

git ls-tree -r --name-only HEAD | while read filename; do
  echo "$(git log -1 --format="%at | %h | %an | %ad |" -- $filename) $filename"
done

Unfortunately, it also fails with non-ascii characters in the filename:

~/example$ tree
.
├── ä_ö_ü.txt
└── foo bar baz.txt

0 directories, 2 files

~/example$ git ls-tree -r HEAD
100644 blob 924665ce4c939bd9fdbfec512cdf379f0c8696c4	foo bar baz.txt
100644 blob 6718a7cf7fb4f41ea7ed4aefad5dd1946a9bb2b4	"\303\244_\303\266_\303\274.txt"

If you want to handle cases where a file has been renamed but not otherwise modified since (and in those cases see the time stamp before the rename), add:

--follow --diff-filter=r

This looks for renames (--follow), then filters them out (lower-case r).

To not have to handle filenames at all in references one can use the object SHA.

Also sending the output to a file for easy sorting and search without having to run the same query many times.

git ls-tree -r HEAD | head | while read MODE TYPE SHA FILENAME; do
  echo $(git log -1 --all --find-object=${SHA} --format="%ad | %h | %an <%ae> |" --date=iso-strict) "${FILENAME}"
done | tee tmpfile.txt

Sort and search

# oldest last
sort -r tmpfile.txt

# find a specific file
grep gitignore tmpfile.txt

Impractical on large repo with more than a couple dozen files, too slow. Muuuch faster:

git log --name-only --date=iso --format="%ad" --reverse | \
awk -v files="$(git ls-tree -r --name-only HEAD | tr '\n' '|')" '
BEGIN {
    gsub(/\|$/, "", files)
    split(files, arr, "|")
    for (i in arr) current[arr[i]] = 1
}
/^[0-9]{4}-/ {date=$0; next}
NF && current[$0] {last[$0] = date}
END {for (file in last) print last[file] " | " file}
' | sort -r