If you want to checkout a file from another branch, do the following.

{{{
[current_branch] $ git checkout <OTHER_BRANCH> -- <FILE>
}}}

Assume you are in branch 'develop' and want to checkout a file from branch master -

{{{
$ git checkout develop
$ git checkout master -- my_file_from_another_branch.txt
}}}

----
[CategoryComputing.SCM.Git]