Counting files between two corresponding strings in multiple directories

Question

Let's say I have some directories which contain files. For example, the directories

/home/me/files/files_10
/home/me/files/files_11
/home/me/files/files_12

each of which contains some files corresponding to the last digits. For example, the directory /home/me/files/files_10 contains files

/home/me/files/files_10/file_100.txt
/home/me/files/files_10/file_102.txt
/home/me/files/files_10/file_105.txt
/home/me/files/files_10/file_106.txt
etc

The file numbers do grow larger, but do not necessarily include each digit (as 101, 103, 104 are missing in this case).

I am seeking to count the number of files between two inputted values. Given the example above, if my first value was 100 and my second value was 105, I would like the output to be 3. If the first value was 103 and the second value was 106, I would like the output to be 2. Furthermore, let's say I give a first value of 112 and a second value of 125. I would like to go into the corresponding directories (ending with 11 and 12), and count the number of files between these two values.

This is a simplified version of what I'm working with, but is functionally equivalent. What scheme could accomplish this? Thanks!

Answer 1

Try this,

 ls /home/test/files/*/file_{112..125}.txt 2> /dev/null | wc -l

Answer 2

You could of course use find but also less frequently used updatedb and locate.

First, we need to use updatedb to create a database of existing files that subsequent locate commands will use. Go to /home/me/files and do:

updatedb --require-visibility 0 -o locate.db -U .

Now we're ready to use locate in conjunction with Bash {a..b} syntax to search for a list of files. For example:

$ locate -d ./locate.db file_{112..125}.txt
./files_11/file_112.txt
./files_11/file_113.txt
./files_12/file_124.txt
./files_12/file_125.txt
$ locate -d ./locate.db file_{100..105}.txt
./files_10/file_100.txt
./files_10/file_102.txt
./files_10/file_105.txt
$ locate -d ./locate.db file_{103..106}.txt
./files_10/file_105.txt
./files_10/file_106.txt

To show only a number of found files pipe locate output through wc -l.

The advantage of this solution is that locate works very fast.

The disadvantage is that you will have re-create the database manually each time new files are added or renamed (or maybe use inotify) and that locate cannot replace found filenames with NUL which will cause wc -l to return incorrect count in case of files that have a new line in their names.

Answer 3

If you're only looking to count the numbered files from x to y included:

$ tree files/
files/
├── file_100.txt
├── file_102.txt
├── file_105.txt
└── file_106.txt

0 directories, 4 files


$ start=103; end=106; echo files/* \
  | grep -o '[[:digit:]]*' \
  | awk '{ if ($1 >='$start' && $1 <= '$end') {++count}} END { print count }'
2

But if you are really sure there are no spaces or linebreaks in your filenames, @msp9011's answer is way easier...