# date +%s
# 1769456599
tee /tmp/commit1-data <<EOF | wc -c
tree d20f1946b531ca91c8e08744c48811593092f23f
author Your Name <your.email@example.com> 1769456599 +0100
committer Your Name <your.email@example.com> 1769456599 +0100

First commit.
EOF
# 182
printf 'commit 182\x00' > /tmp/commit1
cat /tmp/commit1-data >> /tmp/commit1
sha1sum /tmp/commit1
# 09a07a5a0fcba882f3947a63a1aecd8b529a8437  /tmp/commit1
mkdir .git/objects/09
deflate < /tmp/commit1 > .git/objects/09/a07a5a0fcba882f3947a63a1aecd8b529a8437
rm /tmp/commit1 /tmp/commit1-data
mkdir .git/refs/heads
echo 09a07a5a0fcba882f3947a63a1aecd8b529a8437 > .git/refs/heads/master