If you have removed a file (or part of a file) from git, it's not immediately obvious how to query its history. Here are two ways to deal with deleted content in git.

Commit history of a deleted file

If we take the following two files:

$ ls  
file1  file2

and then decide to delete one of them:

$ git rm file2  
rm 'file2'  
$ git commit -m "Delete a file"  
[deletefile 87fadb9] Delete a file  
1 files changed, 0 insertions(+), 1 deletions(-)  
delete mode 100644 file2

To see the commit history of that file, you can't do it the usual way:

$ git log file2  
fatal: ambiguous argument 'file2': unknown revision or path not in the working tree.  
Use '--' to separate paths from revisions

Instead, you need to do this:

$ git log -- file2

Finding the commit that deleted a line

Finding the commit that deleted a line is slightly more complicated. Unfortunately, we can't really use git blame for that. All we can do with git blame is to find the last commit which contained the deleted line.

So if we add the following file:

$ cat file3  
$ git add file3  
$ git commit -a -m "Add a third file"  
[master e62ace6] Add a third file  
1 files changed, 3 insertions(+), 0 deletions(-)  
create mode 100644 file3

and remove the second line:

$ cat file3  
$ git commit -a -m "Remove a line"  
[removeline f3eb691] Remove a line  
1 files changed, 0 insertions(+), 1 deletions(-)

then we can use git blame see what was the last revision to contain each line:

$ git blame --reverse HEAD^..HEAD file3  
f3eb691d (Francois 2010-07-04  1) one  
^e62ace6 (Francois 2010-07-04  2) two  
f3eb691d (Francois 2010-07-04  3) three

Finding the commit that deleted that file requires using git log to search for the text contained on that deleted line:

$ git log --oneline -S'two' file3  
f3eb691 Remove a line  
e62ace6 Add a third file