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Torben Gundtofte-Bruun
Asked: 2014-06-20 06:45:09 +0800 CST

How to mass add file extension?

  • 772

My photo importer moved files from my camera and renamed them, but I forgot to specify that it should keep the file extension. So I have several folders with hundreds of JPG & AVI files that are all missing their proper extension.

There aren't that many video files so I can manually rename them either before of after a general mass-rename to JPG.

To make things more complicated, the filenames contain spaces, so I can't just mv "*" "*.jpg" because, well, that doesn't work (but that's what I'd do, coming from DOS/Windows).

I know Linux is full of powerful commands. How can I mass-rename files to add a .jpg extension, when those files contain spaces?

Please don't say "don't use spaces" because that's really not what I'm asking about. Thanks.

command-line

6 Answers

  1. Best Answer

    Shell globs should work even with spaces in the names if used properly e.g.

    rename -nv -- 's/$/.jpg/' *

    or

    for file in *; do echo mv -- "$file" "$file.jpg"; done

    [NOTE: these are 'no ops' until the n switch or the echo are removed - so you can check the correct replacement before committing]

    If you do want to automatically distinguish between jpg and avi files that would also be possible using a more complex loop and the file or mimetype command

    • 23

  2. If you have a more complex hierarchy, you'll need a slightly more sophisticated approach. You can either use bash's globstar option which lets ** match zero or more directories and subdirectories or you can use find.

    1. globstar

      shopt -s globstar
for f in **/*; do [ -f "$f" ] && mv "$f" "$f".jpg; done

      The [ -f "$f" ] & ensures that the mv command is only run on files and not directories.

    2. find

      find . -type f -print0 | xargs -0 -I{} mv "{}" "{}".jpg

      The -type f ensures we only find files and no directories and the print0 causes find to print its output separated with the null character (\0) instead of newlines. This ensures that we deal correctly with file names containing spaces or newlines or other weirdness.

      xargs takes a list of input and runs the command given on it. The -0 flag tells it to expect null-separated input and the -I{} will make it replace each instance of {} with each of the input records (files in this case) passed.

    • 9

  3. Please refer to man rename before you try this

    This should work like a charm.

    In a terminal: 

    cd /path/to/exported/imgs/folder/
rename  's/(\w+)$/$1\.jpg/' *

    Please change "jpg" to whatever you need.

    rename can use perl expresions.. your best friend

    At first line you entered your files directory

    cd /path/to/exported/imgs/folder/

    The s the before expresion indicates a substitution

    rename  's/(\w+)$/$1\.jpg/' *

    Then will search for any file with an alphanumeric and underscore name , but without extension

    rename  's/(\w+)$/$1\.jpg/' *

    And replace add to it . a dot jpg

    rename  's/(\w+)$/$1\.jpg/' *

    Finally apply to any file in first line folder

    rename  's/(\w+)$/$1\.jpg/' *
    • 5

  4. I would advise you use a program called pyrenamer.

    Open it, and in the Renamed file name pattern, enter {1}.jpg.

    • 4

  5. I encounter this situation quite often administering systems, especially when dealing with filenames created by windows applications. To add .jpg extensions on filenames without any extension, consider this command list.

    find ./example -type f -name '*' -print0 | xargs -0 -I'{}' mv '{}' '{}'.jpg

    find's -print0 generates NULL characters for separators, xargs's -0 is for accepting those NULL separators. This will also do this for any subdirectories, so be sure to replace that './example' path.

    rename is a great command, but it's distro specific in both implementation and specification. I generally use things like rename on the command line, but I always write in GNU utils standards for my scripts.

    • 3

  6. Use this command:

    rename  's/$/.jpg/' *
    • 2