Batch renaming

Problem

This is actually one of the most common problems that we encouter everyday. Sometime somewhere someone will name all the files incorrectly and we want to change the extensions or some part of the filename to suit our needs.

Solution

To change one kind of file name to another, we use bash for loop with find

    # change from .html to .txt
    for file in *.html; do
        mv "$file" "`basename $file .html`.txt"
    done

You can probably do the same with awk as well. The principle is to list the file first then rename them one by one.

However, there's a more convenient way to batch rename, which is the rename command. You can use it like so

    rename 's/\.html$/\.txt/' *.html

The syntax is rename "regex-rule" <files>. So if you can do some simple regex, it's better to do this way.

Another example is to change all filenames to lower case or upper case. Again, you can use rename

    # uppper to lower
    rename -f 'y/A-Z/a-z/' *

    #  lower to uppper
    rename -f 'y/a-z/A-Z/' *