在旧的git commit中从旧名称中查找HEAD文件

Question

Say I know the name of a file in an old commit. But since then, it's been renamed or moved. How can I find it in the HEAD revision, and how can I look at its history from the known old commit up to the present HEAD?

For example, I know in Linux kernel version 3.8, there was a file drivers/usb/gadget/u_serial.c . But in more recent kernels I see that file is no longer there. I'd like to see the file's history from the point I knew in 3.8, up to the present HEAD.

Answer 1

It's a bit sloppy, but the following script will trace the rename history starting from a file which no longer exists:

#!/bin/sh

file=$1

while true
do
    # find the commit in which $file disappeared
    revhash=$(git log --pretty=%H --diff-filter=D -n 1 $revspec -- $file)

    # break out if $file has not disappeared since $revhash
    test -z "$revhash" && break
    revspec=${revhash}..
    echo -n "$revhash renamed $file => "

    # $revhash corresponds to the commit in which $file was removed, i.e. renamed
    # so we combine grep, cut, sed, and diff-tree to figure out what it was renamed to
    file=$(git diff-tree -M --numstat $revhash | grep '=>' | cut -f3- | sed "s/\(.*\){\(.*\) => \(.*\)}\(.*\)/\1\2\4 => \1\3\4/;s/\/\//\//g" | grep $file | sed "s/.* => //")
    echo "$file"
    test -z "$file" && echo -e "???\nNo rename target found, presumably file was deleted." && break
done

and then you can git log --follow the last filename that's returned to you to trace its history.