Use of find command to rename files

findmv

I have a list of 10K mp4 files some of which contains a ? mark. I need to replace these with _ (underscore).

I can use find command to find these files but not sure if I can rename them.

find . -name "*\?*.mp4" -exec mv {} XXXXXXX \;

Looks like I have to iterate through the list returned by find and for each one I need to replace ? with _ but I not sure how to do it.

Best Answer

Don't use find for this - whichever way you go with find you'll need something like a single mv per file. That's a lot of processes, and to no benefit. This is not to mention that it is simply more difficult to do that way. That's my opinion, anyway.

I would use a stream or a batch tool, and tend to prefer pax:

cd -P . && mkdir ../newmp4 &&
pax -rwls'|?|_|g' . "${PWD%/*}/newmp4"

If you can create the directory ../newmp4, that little script will mirror the tree rooted in . to the directory just created with hardlinks, but will have replaced every ? occurring in any filename with an underscore in the meanwhile.

One advantage to this is that both trees continue to exist afterward - none of the dentries rooted in the current directory for those files are affected - they are only altered in the mirrored version of the tree. And so you can inspect the results afterward before deciding which version of the tree to remove. If anything were to go wrong during the operation - there's no harm done.

This does, however, require an fs which supports hardlinks and which has at least as many remaining free inodes as there are child directories of . +2, and assumes that .. . and all children of . share the same filesystem mount.

Practically the same effect might be got with rsync, I think, though I don't believe it is as simply done. If you don't have pax (even if you really should), you can just get it. mirabilos maintains the (to my knowledge) most commonly used version on linux systems.

Related Solutions

Recursively rename files and directories

With find:

find . -type f -exec sh -c 'SHELL COMMAND' {} \;

This invokes SHELL COMMAND on each found file in turn; the file name is "$0". Thus:

find . -type f -exec sh -c '
    mv "$0" "${0%/*}/$(printf "%s\n" "${0##*/}" | sha1sum | cut -d" " -f1)"
' {} \;

(Note the use of printf rather than echo, in case you have a file called -e or -n or a few other problematic cases that echo mangles.)

You can make this a little faster by invoking the shell in batches.

find . -type f -exec sh -c 'for x; do
      mv "$x" "${x%/*}/$(printf "%s\n" "${x##*/}" | sha1sum | cut -d" " -f1)";
    done' _ {} +

In zsh, there's an easy way to match all the files in the current directory and its subdirectories recursively. The . glob qualifier restricts the matches to regular files, and D includes dot files.

for x in **/*(.D); do mv …; done

In bash ≥4, you can run shopt -s globstar and use **/* to match all files in the current directory and its subdirectories recursively. You'll need to filter regular files in the loop.

shopt -s globstar; GLOBIGNORE=".:.."
for x in **/*; do if [[ -f $x ]]; then mv …; done

Rename all files in a directory to the md5 hash of their filename (not content)

You didn't say which shell you want to use, so I'm just assuming Bash – the answer needs adjustments to work with other shells.

for i in *; do sum=$(echo -n "$i"|md5sum); echo -- "$i" "${sum%% *}.${i##*.}"; done

Script version:

for i in *; do
  sum=$(echo -n "$i" | md5sum)
  echo -- "$i" "${sum%% *}.${i##*.}"
done

This simple for loop takes every file in the current directory, computes the md5 sum of its name and outputs it. Use this to check the functionality, if you want to start renaming replace the second echo by mv.

Explanations

echo -n "$i" | md5sum – calculate md5 sum of the full file name including the file extension (Piping), to strip the extension change echo -n "$i" to one of the following:
```
${i%%.*}
sed 's/\..*//' <<< "$i"
echo "$i" | sed 's/\..*//'
```
sum=$(…) – execute … and save the output in $sum (Command Substitution)
${sum%% *} – output everything until the first space (Parameter Substitution), the same as one of the following:
```
$(sed 's/ .*//' <<< "$sum")
$(echo "$sum" | sed 's/ .*//')
```
${i##*.} – output everything after the last dot (Parameter Substitution), the same as one of the following:
```
$(sed 's/.*\.//' <<< "$i")
$(echo "$i" | sed 's/.*\.//')
```

If you need to rename files recursively in different folders, use find with the -exec option.

Best Answer

Related Solutions

Recursively rename files and directories

Rename all files in a directory to the md5 hash of their filename (not content)

Explanations

Related Question