ls or dir - limit the number of file name returns

Is there a way to limit the number of filenames to be returned using the ls or dir command? I'm on a windows machine with cygwin, so either comman开发者_StackOverflowd will do.

I have a directory with over 1 million docs that I need to batch out into subfolders. I'm looking to write a simple script that would list the first 20,000 or so, move them to a subfolder, then repeat on the next 20,000. I would expect ls or dir to have an option to list only a certain number of files, but I can't seem to find a way to do it.

My other option is to print the filenames out to a text file and parse that to make the moves. It seems like there should be a simpler solution though.

If you are using cygwin, you should be able to use the head command, like this:

ls | head -20000

to list the first 20 thousand.

If you want to move the batch in 1 command line, something like this should work:

ls | head -20000 | xargs -I {} mv {} subdir

(where subdir is the subdir you want to move the files to).

Run this first (with the echo command) to verify it will work before running the actual move:

ls | head -20000 | xargs -I {} echo mv {} subdir

Just be careful though, since you are moving files into a subdir, because the "ls" command will probably pick up your subdirs as well.

If they are all txt files, you could do something like this:

ls | grep txt$ | head -20000 | xargs -I {} mv {} subdir

to get files that end in txt

Or you might want to combine head and tail to fetch entries out of the middle:

Example data:

banana
cherry
apple
orange
plum
strawberry
redcurrant

Now let's skip 2 entries and fetch the following 2 ones:

cat fruit.txt | head -n 4 | tail -n 2

That will give you:

apple
orange

So head -n 4 will return the first 4 entries (banana to orange) and the following tail -n 2 will get the last 2 ones out of that previous result (apple to orange) and not out of the original file.