Avoid replacing spaces when renaming files

Question

I'm trying to rename files like this:

for file in *;
do
mv -i "$file" "$(echo "$file" | sed -e 's/[^A-Za-z0-9._-]/_/g')";
done

But the sed command replaces all spaces with _.

How can I edit the sed command to make it inlcude spaces along with the specified characters? I've tried using \s but it does not work...

EDIT:
For example: the file trip: hill, should be renamed: trip_ hill, but the command above makes it trip__hill.

Answer 1

Do not parse filenames with sed! The output of echo "$file" may not be reliable.

Use rename. On 17.10 you need to install it first

sudo apt install rename

Then:

rename -n -- 's/[^-A-Za-z0-9_ .]/_/g' *

Notes

• remove -n after testing to actually rename the files
• -- end-of-options in case any file begins with -
• [^-A-Za-z0-9_ .] characters we do not want to replace - put - first or last so it can't indicate a range (it is treated literally in these positions).
• Spaces can be included in the class
• . is treated literally (in other regex contexts it stands for any character and needs to be escaped).

This also works in sed:

$ echo 'trip: hill' | sed 's/[^-A-Za-z0-9 _.]/_/g'
trip_ hill

If I add a space to the end in your version, I get an error:

$ echo 'trip: hill' | sed -e 's/[^A-Za-z0-9._- ]/_/g'
sed: -e expression #1, char 22: Invalid range end

But with - at the end, it works:

$ echo 'trip: hill' | sed -e 's/[^A-Za-z0-9._ -]/_/g'
trip_ hill

So perhaps the position of the hyphen caused your problem when you added the space. But the advice not to parse filenames stands!

Answer 2

You can also just use the shell, Bash's parameter expansion can do substitution:

for f in ./* ; do
    mv "$f" "${f//[^-A-Za-z0-9._ ]/_}"
done

The double slash tells it to replace all matches, other than that, the syntax is straightforward.