I also think Org-mode table src block content to override file is dangerous.

I have another idea. Append src block content to end of file.

I have a sceniro:

File `dotfile-1.org`:
```
* SSH config 1

#+BEGIN_SRC conf :tangle "~/.ssh/config"
fragment 1
#+END_SRC
```

File `dotfile-2.org`:
```
* SSH config 2

#+BEGIN_SRC conf :tangle "~/.ssh/config"
fragment 2
#+END_SRC

```

When the tangle src blocks are in separate files, this override file way is
not suitable.
Of course I can put those src blcoks together, but when I have to organize
literate programming files in separately, the override way is not suitable
anymore. So hope Org-mode can provide `append` way with an `defcustom`
option.


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On Fri, Jun 16, 2017 at 1:09 PM, Chunyang Xu <mail@xuchunyang.me> wrote:

> Hi,
>
> Currently 'C-c C-v C-t' ('org-babel-tangle') simply overrides existing
> tangle-file, I would like org to ask me what to do? such as
>
> a) yes (override)
> b) no (don't override)
> c) show the diff then ask again
>
> In addition, if there is no diff (i.e., having the same contents), user
> can choose (e.g., via a user option) to simply pass this tangle-file
> without overriding.
>
> I am asking for this feature because I am storing my dotfiles in a
> single Org file [1], and when I change my Bash configuration then
> tangle, I don't need to worry if Org is tangling other configuration
> correctly, especially ~/.ssh/id_rsa and ~/.authinfo.gpg. I would rather
> leave these unchanged files than override (even only file modification
> timestamps are updated).
>
> [1] https://raw.githubusercontent.com/xuchunyang/dotfiles/
> master/README.org
>
>
>
>