How to create list of files that is recursive and output as txt file?

This issue

I have a folder with about 10,000 files in it.  I want to scan through the directories and isolate files that are different from what sits in the database.  How do you generate a list of file names of all the files into a single txt file?

Solution

One option is using the list command

ls > filename-list.txt

However, this option will generate a list of the current directory, listing directories by name only and therefore not including file from each of the directories contained within.

Second option is using the find command

Using the find command, there are key extensions to be aware of...

Search by type

You can use the following option if you want to search for a specific file type:

• b – block devices
• c – character devices
• d – directory
• f – regular file
• l – symbolic link

Search by name

Name type - hmmm, how can I use the name extension as I don't want to find a specific file name.  As I want to find PDF's, I can leverage the -name and add the following

-name '*.pdf'

Search Files by Size

To search all files less than 4MB

-size -4M

Or if you want to search a size range, such as all files between 3MB and 8MB

-size +3M -size 8M

Use the following options to specify the size in KB, MB, GB, and more.

• b – bytes
• k – Kilobytes
• M – Megabytes
• G – Gigabytes

Search Files by Modification Time

Want to search a file based on its modification, access and change time?  To search files inside a directory that have been modified in the last n days... like in the past 15 days

-mtime 15

Inversely, you can use the + symbol if you want to find all files that have been modified more than n days... such as 5 days

-mtime +5

Search Files by directory depth

Manage the depth of directories that find for the n directories... such as 10 directories recursively

-maxdepth 10

Pulling the query together

To begin I'll use directory depth and file type:

find files -type f -maxdepth 10 > filename-list.txt

However, the response showed a failure...

find: warning: you have specified the global option -maxdepth after the argument -type, but global options are not positional, i.e., -maxdepth affects tests specified before it as well as those specified after it.  Please specify global options before other arguments.

Moving the position of max depth did the trick

find files -maxdepth 10 -type f > filename-list.txt

I want to also limit the find to PDF files

find files -maxdepth 10 -type f -name '*.pdf' > filename-list.txt