How to prevent `mv` from moving a collection of files into a single regular one?

Question

I've just lost a small part of my audio collection, by a stupid mistake I made. :-(
GLADLY I had a fairly recent backup, but it was still irritating. Apart from yours truly, the other culprit doing the mischief was mv, which will show as follows:

The audio files had a certain scheme:

ARTIST - Some Title YY.mp3

where YY is the 2-digit year specification.

mkdir 90<invisible control character>

(Up to this moment, I did not know that I had actually typed one third excess character which was invisible ...!)
Instead of having all in one directory, I wanted to have all 1990s music in one directory. So I typed:

find . -name '* 9?.mp3' -exec mv {} 90 \;

Not so hard to get the idea what happened eh? :->
The (disastrous) result was a virgin empty directory called '90 something' (with something being the "invisible" control character) and one single file called '90', overwritten n times.

ALL FILES WERE GONE. :-(( (obviously)

Wish mv would've checked in time whether the signature of the destination "file" (remember on *NIX: Everything Is A File) starts with a d------ (e. g. drwxr-xr-x). And, of course, whether the destination exists at all. There is a variant of the aforementioned scenario, when you simply forgot to mkdir the directory first. (but of course, you assumed that it's there...)

Even our pet-hate OS starting with the capital W DOES DO THIS. You get even prompted to specify the type of destination (file? directory?) if you ask for it.

Hence, I'm wondering if we *NIXers still have to write ourselves a "mv scriptlet" just to avoid these kinds of most unwanted surprises.

Answer 1

You can append a / to the destination if you want to move files to a directory. In case the directory does not exist you'll receive an error:

mv somefile somedir/
mv: cannot move ‘somefile’ to ‘somedir/’: Not a directory

In case the directory exists, it moves the file into that directory.

Answer 2

The GNU coreutils mv already has an option specifying that you want to move to a directory: -t / --target-directory. If the argument to that option doesn't exists, mv will complain instead of moving all of your files to the same filename.

I would have written your mover as follows:

find . -name '* 9?.mp3' -exec mv -t 90 {} +

Note the use of + instead of \;, globbing as many filenames together as possible, resulting in faster execution.

Answer 3

Additionally, if you generally plan to avoid accidental overwrites in the future, there is the -i option for mv. I personally cannot think of any drawbacks if you

alias mv='mv -i'

If you then need to overwrite something, simply pass the -f option.

Aliases only take effect if you type the command directly into an interactive shell, not for cases like invocation by find. You could have run

find . -name '* 9?.mp3' -exec mv -i {} 90 \;

and then you would have been prompted if mv had tried to overwrite an existing file.

Answer 4

In addition to the excellent answers above, I'd like to clarify why you didn't get the question about whether to move the files or not.

If you move one file to a new name, and that name is not a directory, mv will rename your file to the new name.

The issue here is that you were using find to execute mv once per file, not once for all the files.

If, instead, you'd done mv *90.mp3 90, then mv would have failed with the error message that "the target file is not a directory".

Another piece of advice is to use tab completion when typing the target path. It will show you whether the target is a directory by adding / to the target name. You can also use mv -i to be asked whether you want to overwrite an existing file.

Answer 5

As an alternate general-purpose strategy I'd like to suggest turning this kind of operation into a temporary script. I prefer to look at the results of find and turn them into a mv command by hand, ensuring that I understand what I'm doing before I execute. eg.

find . -name '* 9?.mp3' > tmp
vim tmp

Now I can look through a list of filenames and rewrite the file contents as a shell command.

• Put the file contents on one line: ggVGJ
• Prepend: Imv [esc]
• Append: Asomedir/ [esc]
• Save the file. Read it again. Take a breath.
• Execute source tmp on the command line.

It is a conservative strategy, but I've been bitten too often by mistyped -exec or sed commands, or misunderstood shell expansions, and I prefer taking a slow consistent approach.

In other words: I am too cowardly to use -exec.

Answer 6

Another option:

-n, --no-clobber do not overwrite an existing file

it's the same as -i, but it wont ask, it'll fail.