Renaming files in linux with a regex

Question

I had a group of files that I'd like to consistently rename, the files are named things like

"System-Log-01-01-2009-NODATA.txt"
"Something-Log-01-01-2009-NODATA.txt"

And I wanted them as lowercase, yyyymmdd, .log extension

"system.20090101.log"
"something.20090101.log"

Answer 1

I used to write perl scripts to do this, until I discovered the rename command.

It accepts a perl regex to do the rename:

for this, I just typed two commands:

rename 's/(\w+)-(\w+)-(\d\d)-(\d{4})-NODATA.txt\$1.$4$3$2.log$//' *
rename 'y/A-Z/a-z/' *.log

Answer 2

mmv is a standard linux utility to move/rename multiple files. It is available from the repos for most distributions. For your example above, you could do:

mmv *-Log-*-*-*-NODATA.txt #l1.#4#3#2.log

For more information, read this debaday article or the man page.

Answer 3

rename util is not very "standard". Each distro ships with a different rename tool. For instance, here on Gentoo, rename is from sys-apps/util-linux package and does not support regex.

Hamish Downer suggested mmv, it seems useful, specially for use inside scripts.

On the other hand, for the general case, you might want renameutils. It has qmv and qcp commands, which will open a text editor of your choice (my preference: Vim) and allow you to edit the destination filenames there. After saving and closing the editor, qmv/qcp will do all the renaming.

Both mmv and qmv are smart enough to rename files in correct order and also to detect circular renames, and will automatically make a temporary file if needed.

Answer 4

To be fair:

rename 's/(\w+)-(\w+)-(\d\d)-(\d{4})-NODATA.txt\$1.$4$3$2.log$//' *.txt

gives this output:

Use of uninitialized value $4 in regexp compilation at (eval 1) line 1.
Use of uninitialized value $3 in regexp compilation at (eval 1) line 1.
Use of uninitialized value $2 in regexp compilation at (eval 1) line 1.

But:

rename -n 's/(\w+)-\w+-(\d{2})-(\d{2})-(\d{4})-NODATA\.txt$/$1.$4$3$2\.log/' *.txt && rename 'y/A-Z/a-z/' System.20090101.log

gives the right output:

System-Log-01-01-2009-NODATA.txt renamed as System.20090101.log
System.20090101.log renamed as system.20090101.log

replacing {-n} switch with {-v}

Answer 5

Since i don't have a rename command, i am relying on this:

for myfile in /my/folder/*; do
    target=$(echo $myfile|sed -e 's/foo/bar/g')
    mv "$myfile" "$target"
done