how to create the patch from current file

how to create the patch from current file

[Michal]

Hallo group readers.

Imagine the following situation:
I just changed some part of file, but did not save it.
Now I want to create a patch comparing to the original file.
Do You know any emacs command that would do it for me?

Optionally I can imagine that this might even be possible after I saved
a file. Then file~ could be used as a version before changes?

best regards,
Michal

Re: how to create the patch from current file

[Teemu Likonen]

On 2009-07-15 11:22 (+0200), Michal wrote:

> Imagine the following situation:
> I just changed some part of file, but did not save it.
> Now I want to create a patch comparing to the original file.
> Do You know any emacs command that would do it for me?

 a) M-x diff-buffer-with-file

 b) Save the file with C-u C-u C-x C-s, that is, the normal save command
    with two prefix arguments. It will force the previously saved file
    to become backup file and the current version is saved as the main
    file. Then compare them.

Re: how to create the patch from current file

[Pascal J. Bourguignon]

Teemu Likonen <tlikonen@iki.fi> writes:

> On 2009-07-15 11:22 (+0200), Michal wrote:
>
>> Imagine the following situation:
>> I just changed some part of file, but did not save it.
>> Now I want to create a patch comparing to the original file.
>> Do You know any emacs command that would do it for me?
>
>  a) M-x diff-buffer-with-file

That's great! 


>  b) Save the file with C-u C-u C-x C-s, that is, the normal save command
>     with two prefix arguments. It will force the previously saved file
>     to become backup file and the current version is saved as the main
>     file. Then compare them.

-- 
__Pascal Bourguignon__

Re: how to create the patch from current file

[Michal]

Teemu Likonen <tlikonen@iki.fi> writes:

>  a) M-x diff-buffer-with-file
>
>  b) Save the file with C-u C-u C-x C-s, that is, the normal save command
>     with two prefix arguments. It will force the previously saved file
>     to become backup file and the current version is saved as the main
>     file. Then compare them.


Thank All of You for great help.
regards

Re: how to create the patch from current file

[Pascal J. Bourguignon]

Michal <rabbitko@tenbit.pl> writes:

> Hallo group readers.
>
> Imagine the following situation:
> I just changed some part of file, but did not save it.
> Now I want to create a patch comparing to the original file.
> Do You know any emacs command that would do it for me?

C-x C-w newfile RET
M-x diff RET newfile RET oldfile RET

Eventually: M-x rename-file RET newfile RET oldfile RET
to override the oldfile by the newfile.


> Optionally I can imagine that this might even be possible after I saved
> a file. Then file~ could be used as a version before changes?

Don't count on it.  The time when a backup file is created is not
always what you'd want it to be.

-- 
__Pascal Bourguignon__

Re: how to create the patch from current file

[Bernardo]

Teemu Likonen said the following on 15/07/09 19:40:
> On 2009-07-15 11:22 (+0200), Michal wrote:
> 
>> Imagine the following situation:
>> I just changed some part of file, but did not save it.
>> Now I want to create a patch comparing to the original file.
>> Do You know any emacs command that would do it for me?
> 
>  1) M-x diff-buffer-with-file
> 
>  2) Save the file with C-u C-u C-x C-s, that is, the normal save command
>     with two prefix arguments. It will force the previously saved file
>     to become backup file and the current version is saved as the main
>     file. Then compare them.
> 
an alternative is (before saving the file) to type:
C-x s d
this will show you the diff

if you bail out with C-g you can still switch back to *Diff* buffer and 
save it