neoneye neoneye - 2 months ago 14
Git Question

git-checkout older revision of a file under a new name

I have the file "

main.cpp
" open in my editor.

I want to see the previous revision of "
main.cpp
" in the editor too.

The way I do it now is like this.

close "main.cpp" in the editor

prompt> mv main.cpp tmp
prompt> git checkout HEAD^ main.cpp
prompt> mv main.cpp old_main.cpp
prompt> mv tmp main.cpp
prompt>

open "main.cpp" and "old_main.cpp" in the editor


Can it be simplified, so I don't have to close "main.cpp" in the editor?

What I'm hoping for is a variant of
git-checkout
that can do this.




UPDATE: im using git on mac osx 10.5.7

prompt> git --version
git version 1.6.0.4
prompt>





UPDATE2: Jakub Narębski answer is:

prompt> git show HEAD^:dir1/dir2/dir3/main.cpp > old_main.cpp
prompt>





UPDATE3: Karmi's answer, for a specific revision:

prompt> git show 4c274dd91dc:higgs/Higgs.xcodeproj/project.pbxproj > old_project.pbxproj
prompt>

Answer

You can use "git show" for that:

prompt> git show HEAD^:main.cpp > old_main.cpp

(Note that there is colon ':' character between HEAD^ and main.cpp`.) The "<revision>:<path>" syntax is described in git rev-parse manpage, next to last point in the "Specifying revisions" section:

  • <rev>:<path>, e.g. HEAD:README, :README, master:./README

    A suffix : followed by a path names the blob or tree at the given path in the tree-ish object named by the part before the colon. :path (with an empty part before the colon) is a special case of the syntax described next: content recorded in the index at the given path.

    A path starting with ./ or ../ is relative to the current working directory. The given path will be converted to be relative to the working tree’s root directory. This is most useful to address a blob or tree from a commit or tree that has the same tree structure as the working tree.

Note that "<path>" here is FULL path relative to the top directory of your project, i.e. the directory with .git/ directory. (Or to be more exact to "<revision>" (which in general can be any <tree-ish>, i.e. something that represents tree))

If you want to use path relative to the current directory, you need to use "./<path>" syntax (or "../<path>" to go up from current directory).

Edit 2015-01-15: added information about relative path syntax


You can get in most cases the same output using low-level (plumbing) git cat-file command:

prompt> git cat-file blob HEAD^:main.cpp > old_main.cpp
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