Recursively remove files with idx > 10,000

Question

The problem

In the current working directory I have several (very many) folders and some of them have lots (like 100,000+) of files inside.

My goal is getting just the folder with 10,000+ files and delete folderName10001.ext and above (where folderName is the actual name of the containing folder and ext is a whatever extension).

Approach taken

I am trying to print nameFolder numberOfFiles with bash.

find . -maxdepth 1 -type d -name 'acer' -exec sh -c "echo {}; ls {} | wc -l" \;

This works just fine (for the sample folder acer), but the output is

./acer
6058

I would like to have 1-line output per folder

find . -maxdepth 1 -type d -name 'acer' -exec sh -c "echo {} `ls {} | wc -l`" \;

says ls: cannot access {}: No such file or directory.

---

Questions

1. How can I get to display in one line nameFolder numberOfFiles?
2. Is there an easier way to delete every file folderName/folderName#.ext, with # > 10000?

Question 2

Some more details may help understand what's going on.

I have a folder with the following tree

.
├── a
│   ├── a1.ext
│   ├── a2.ext
│   ├── a3.ext
│   └── a4.ext
├── b
│   ├── b1.ext
│   ├── b2.ext
│   ├── b3.ext
│   └── b4.ext
└── c
    ├── c1.ext
    ├── c2.ext
    ├── c3.ext
    └── c4.ext

I'd like to remove every file with a number greater than 2. (In my specific case the threshold is set to 10000.)

---

Answer 1

It's all about who interprets what (thanks to @Bratchley for the advise in the comments).

Since I'm typing into bash, bash gets first to interpret what I type. If I want bash to send to find's bash a backtick, then I need to escape it.

find . -maxdepth 1 -type d -name 'acer' -exec sh -c "echo {} \`ls {} | wc -l;\`" \;

which gives me

./acer 6058

@Barmar points out that single- and double-quotes behaves differently, and therefore

find . -maxdepth 1 -type d -name 'acer' -exec sh -c 'echo {} `ls {} | wc -l`' \;

would work just fine (note " replaced with ').

Answer 2

This has been provided by Walter A, and it is the accepted answer for this question.

More errors (a couple of examples follows)...

black: 390120
./clean.sh: line 6: /bin/ls: Argument list too long
rm: missing operand
Try 'rm --help' for more information.

leather: 118240
./clean.sh: line 6: /bin/ls: Argument list too long
rm: missing operand
Try 'rm --help' for more information.

OK, I've fixed it with

ls -d */ | cut -d/ -f1 | while read dir; do
COUNT=$(ls $dir | wc -l);
   if [ ${COUNT} -gt 10000 ]; then
      echo "$dir: ${COUNT}" ;
      for i in `seq 10001 ${COUNT}`; do
         rm ${dir}/${dir}${i}.*
      done
   fi
done

Answer 1

Use single quotes instead of double quotes, so that backticks and $ don't get interpreted by the original shell:

find . -maxdepth 1 -type d -name 'acer' -exec sh -c 'echo {} $(ls {} | wc -l)' \;

For the second question, I would put what you want to do into a separate script, that takes the directory name as an argument. Then do:

find . -maxdepth 1 -type d -name 'acer' -exec ./scriptname {} \;

This way you don't have to deal with all the quoting issues from using -exec sh -c.

Answer 2

You could write

ls -d */ | while read dir; do
    echo "$dir: $(ls $dir | wc -l)"
done

When the filenames are numbered without leading zeroes, you can try

ls -d */ | cut -d/ -f1 | while read dir; do
     COUNT=$(ls $dir | wc -l);
     echo "$dir: ${COUNT}" ;
     if [ ${COUNT} -gt 10000 ]; then
        ls ${dir}/${dir}?????*.ext | grep -v ${dir}/${dir}10000.ext | xargs rm
     fi
done

Another approach would be possible when you have leading zeroes in the filenames:

ls -d */ | cut -d/ -f1 | while read dir; do
   ls ${dir}/${dir}*.ext | tail -n +10001 | xargs rm
done

Edit: Included dir+filename in ls commands, and I added cut -d/ -f1 | to cut off the trailing /.