Question

I’m trying to rename files with spaces and other such script breaking characters in them.

The platform is Ubuntu server 12 (with Bash 4) and any instance of the ‘rename’ command refers to Prename aka Perl Rename.

I’m either having a problem writing a suitable regex, or I’m having a problem creating a valid variable from the find command.

Here’s my maturely named test data (all files, no directories):

/test/-poop
/test/poopfile.txt
/test/po_________!!!!!!!! $$^^^   op.sh

(EDIT) Expected output: I want to change the filenames to

/test/poop
/test/poopfile.txt
/test/po_op.sh

(/EDIT)

If I run this command in /test:

find * -type f -exec rename -n 's/[^a-zA-Z0-9-_.]/_/g; s/_+/_/g' {} \;

I of course get:

find: unknown predicate `-poop'

So I changed things: (find * -> find . so that the results of the find command are prefixed with ./)

find . -type f -exec rename -n 's/[^a-zA-Z0-9-_.]/_/g; s/_+/_/g' {} \;

Which returns

./-poop renamed as ._-poop
./poopfile.txt as ._poopfile.txt
./po_________!!!!!!!! $$^^^   op.sh renamed as ._po_op.sh

That’s no good. All my files are now prefixed _ because my regex did exactly what I told it to. If I didn’t have to cope with files that had a leading “-” then I’d be fine, but that’s exactly the kind of thing I’m trying to treat with this script.

This is where I’m stuck – I can’t figure out how to get my regex to not match either the first two characters in a line, or the first instance of “./”

^.{2} ## matches the first two characters in the string
^./   ## matches the ./ at the start of the line (assuming I change my delimiter from /)

But how do I say “Anything that is NOT the first two characters in the string and is NOT a character in [a-zA-Z0-9.-_]?”

OR

Am I doing this entirely wrong? Is there a way that I can pass the results of the find command to the rename script so that a leading “-” does not cause find to barf?

Actually thinking on those lines – I wrote this:

for f in $( find . -type f ); do
    p=$( printf "%s\n" "$f" | sed 's/^..//' );
    rename -n 's/[^a-zA-Z0-9-_.]/_/g; s/_+/_/g' "$p";
done

Result:

Unknown option: p
Unknown option: o
Unknown option: o
Unknown option: p
Usage: rename [-v] [-n] [-f] perlexpr [filenames]

So even if I can get find to hand “-poop” to rename as “-poop” it’s still barfing on the leading hyphen.

Pretty sure the answer lies in the regex.

I’m very grateful for any guidance that can be offered! This is my first question here – please let me know if I’ve made mistakes or etiquette errors. I’m very aware that my knowledge of regex is poor, but I think I’ve reached the point on this where not asking a question would be the silly course of action.

Answer 1

Use rename -n -- $regex $filenames.

The key here is --, which is a widely used method of saying “options end here, filenames start here”. find itself doesn’t support it, but rename does.

Some more details here.