I have 1,000,000 files in some folders and subfolders. I want to rename them from lowercase to uppercase using shell commands. I don't want to modify the extension. only filename part.

I have found this one:

rename 's/^([^.]*)\.(.*)$/\U$1\E.$2/' *

but it is not recursive and only works on files in current folder.

Then I tried this one:

find . -depth  -execdir rename 's/^([^.]*)\.(.*)$/\U$1\E.$2/' {} \;

But no files changed.

How can I use it recursively?


Assuming that you have the Perl rename provided by Debian and derived distributions such as Debian and Ubuntu, you're almost there. The problem is that -execdir passes a file name prefixed with ./ to the command. (The reason for that is that some commands treat arguments starting with some characters specially; this way, if you have a file called -foo, it's passed as ./-foo and therefore treated as a file and not as an option.) With your regex, this results in $1 being always empty, and hence the new name is identical to the old name.

Accommodate for this ./ in your regular expression.

find . -depth  -execdir rename 's/^(\.\/[^.]*)\.(.*)$/\U$1\E.$2/' {} \;
  • The above command fails on directory name with a dot(.) separator. ex : dir.xyz/abc.txt is being renamed to DIR.xyz/ABC.txt
    – Priya
    Jul 25 '13 at 5:00
  • It is ambiguous in the OP whether files or {files and directories} were to be changed. I read -type f and Giles infers the opposite. We're both wrong and both right.
    – msw
    Jul 25 '13 at 5:21
  • @Ameer rename will never be called with an argument of the form dir.xyz/abc.txt, because -execdir was used and not -exec. All the arguments to rename will be of the form ./SOMETHING where SOMETHING doesn't contain any slash. So dir.xyz will be renamed to DIR.xyz, which is consistent with the expressed requirements. Thanks to -depth, this happens after dir.xyz/abc.txt has been renamed to dir.xyz/ABC.txt, so there won't be a problem with find attempting to move into a directory that's been renamed without it knowing. Jul 25 '13 at 11:18

find . -type f -exec rename -v 's/(\w+).(\w+)$/\U$1\E.$2/' {} \;

  • This is close to correct but it will fail on filenames with spaces or punctuation in them. It would also be a better answer if you explained why you are using -type.
    – msw
    Jul 24 '13 at 10:04
  • @msw What problem do you see with file names with whitespace? This will, however, fail on files in subdirectories that contain lowercase letters, as it will attempt to rename e.g. foo/bar.ext to FOO/BAR.ext (hd. used -execdir to work around this problem). Jul 24 '13 at 21:56
  • @Gilles , there is no fail with directory as -type f only gives the file path. and renames $1 & $2 only touches the files inside the dir.
    – Priya
    Jul 25 '13 at 5:01
  • @Giles I think you know the answer as you used the more inclusive pattern in your answer, but \w+ will not match test file or test-file and many other such likely names. It also uses . when it should have \.. Also since @Ameer commented while I was writing this, without -execdir you need to ensure that only the last path component is matched yielding (untested) s!/([^/]*)\.([^/]*)$!—!
    – msw
    Jul 25 '13 at 5:08

You can use this little bash script.


find . -type f -exec sh -c  '
    dn=`dirname "$1"`
    bn=`basename "$1"`
    fn=`echo "${bn%.*}"`
    ext=`echo "${bn##*.}"`
    FN=`echo "${fn^^}"`
    #echo ${dn}/$newfn
    if [ "${fn}" = "${FN}" ] ;then : ;else echo "${bn} renamed to ${newfn}";mv "$1" "${dn}/${newfn}";fi
' _ {} \;
  • And how will that traverse the directory structure recursively, as requested in the question?
    – manatwork
    Jul 24 '13 at 12:22
  • @manatwork: This new script takes into consideration the subdir part of the question that I overlooked before.
    – Luis
    Jul 24 '13 at 12:36
  • 1
    Ok, it works fine now. But why you use fn=`echo "${bn%.*}"` instead of fn="${bn%.*}"?
    – manatwork
    Jul 24 '13 at 12:46
ls -r | rename 's/^([^.]*)\.(.*)$/\U$1\E.$2/'

Is this OK?

  • never use ls for anything Jul 24 '13 at 10:29
  • 3
    Except listing the contents of filesystems? I find find -maxdepth 1 -ls to be a bit of a nuisance for that. ;) But joking temporarily aside, parsing ls is a baaaad idea unless you're doing something very constrained and well-defined. And probably not even then.
    – Alexios
    Jul 24 '13 at 11:14
  • Wondering who upvoted a ls call with --reverse instead of --recursive?
    – manatwork
    Jul 24 '13 at 12:43

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