I don't know if any of you are familiar with Perl Golf, but I'm just learning some of the subtleties of the language and was wondering if you could help me shorten some code I wrote. The "one-line" script renames all jpg files in the current directory to be "pic0.jpg" "pic1.jpg" ... "pic(n).jpg" etc for all jpg files. I've written it for both windows based and unix based systems. Here it is:

perl -e "$c=0; while(`dir /B` =~ m/(\S.*\.jpg)/g) { push @a, $1} for(@a) { rename $_,'pic'.$c.'.jpg' unless (-e 'pic'.$c.'.jpg'); $c++ }"

perl -e '$c=0; while(`ls -F` =~ m/(\S.*\.jpg)/g) { push @a, $1} for(@a) { rename $_,"pic$c.jpg" unless (-e "pic$c.jpg"); $c++ }'

As a not one line command, it would look like this (for unix)


Let me know if you have can think of any ways to shorten it. Or have a better way of approaching the problem.

rename $_,"pic@{[$c++]}.jpg" for <*.jpg>

I'm not a golfer, but the first thing that came to mind is that your array (@a) is completely unnecessary and doesn't serve any obvious purpose beyond making the code longer.

is exactly equivalent, without going through the trouble of building and reading from the array.

This can be further tightened up by looking at KevinADC's version, but note that his doesn't include the protection against clobbering existing files.

Wow, that is concise.

I actually tried that (I think). My problem is that `ls -F`, as well as the dir command I use for windows, lists them alphabetically. so let's say there are 3 pictures titled:
After the first iteration of the loop, the files are as follows (In alphabetic order - because that's how ls -F will show them)
The first iteration found the first file and changed it. In the next iteration, the while loop will find the second file, which is now duck.jpg and not car.jpg, and change it.

During the last iteration, the script will look at pic1.jpg, but not change it b/c I told it not to. (This prevents a file overwriting a file that already exists).

@KevinADC
Now, let's say I want to all of the files that are something like "auto.*" (like auto.jpg, auto.txt, etc) and change them to "car.*" Could I just change your script to for <auto.*>? I realize I would have to change the regular expression a bit to store the file extension in $2 or something, but I'm more curious about the for loop.

if you want to find all files in a directory that start with auto then yes, you can use <auto*>.

On a more practical note, the glob() function is better used in perl code than the <*> type glob.