Can a file added to the index be retrieved?

Question

As I read through as many sources on how to use git, I haven't come across any article which suggests when you can rollback should the need arise. So for example I have initialized a git directory in my working directory i.e. git init

I then add files to git's index i.e. git add .. This has added all files to git's index. Now rather than committing the files to git's repository i.e. git commit, I make a change to one of the files I added to the index. I realize I made a mistake. Can I rollback to the previous state or is this only possible when I have committed the file? My understanding is that when I run the command git add . a copy of the file or files is made in git's object store. I believe the files in the object store are compressed. Does this mean I can rollback from the object store?

score 2 · Accepted Answer · answered Jan 24 '13 at 00:59

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Yes, you can. Try

git checkout-index -f foo

to checkout foo from index. Or checkout all files by

git checkout-index -fa

answered Jan 24 '13 at 00:59

dyng

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Is `foo` the file I added to the index? What happens when I checkout the file? Does it overwrite my changes? Does it merge them? – PeanutsMonkey Jan 24 '13 at 01:05
Yes. It will overwrite the file in working directory, not merge. – dyng Jan 24 '13 at 01:08
It will overrite them. The `-f` is meant to force the operation in case a file already exists. – Maic López Sáenz Jan 24 '13 at 01:08
But really, I think just `git checkout -- foo` is a better way. I missed it. – dyng Jan 24 '13 at 01:12

score 2 · Answer 2 · answered Jan 24 '13 at 01:00

2

Use

git checkout -- <file>

to discard changes in working directory while keeping changes to index.

answered Jan 24 '13 at 01:00

Zombo

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Is `` the name of the file I added to the index? – PeanutsMonkey Jan 24 '13 at 01:06

score 1 · Answer 3 · answered Jan 24 '13 at 01:00

1

Using git checkout without specifying a tree-ish will checkout from the index.

answered Jan 24 '13 at 01:00

Maic López Sáenz

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Sorry for being a n00b. What does that mean exactly? – PeanutsMonkey Jan 24 '13 at 01:04
Usually you use `git checkout ` to checkout a branch, tag, HEAD, or a specific commit. If you dont use that parameter the checked out content will come from the index. For what is a treeish check: http://stackoverflow.com/questions/4044368/what-does-tree-ish-mean-in-git – Maic López Sáenz Jan 24 '13 at 01:13

score 1 · Answer 4 · answered Jan 24 '13 at 01:08

I got intrigued by the question and the answer appears to be "yes", git add puts a copy of the file in the repository and you can rollback the file even if no commit has been made in the repository, tested with the following example.

% mkdir test && cd test
% git init .
% echo "1" > test.txt
% git add test.txt
  - git status shows now "added" file
% echo "2" > test.txt
  - git status shows "added" and "modified" file, test.txt contains number 2
% git checkout test.txt
  - git status shows only "added" again, and test.txt contains the number 1

Can a file added to the index be retrieved?

4 Answers4