Find the files existing in one directory but not in the other [closed]

I'm trying to find the files existing in one directory but not in the other, I tried to use this command:

diff -q dir1 dir2

The problem with the above command that it finds both the files in dir1 but not in dir2 as well as the files in dir2 but not in dir1,

I am trying to find the files in dir1 but not in dir2 only.

Here's a small sample of what my data looks like

dir1    dir2    dir3
1.txt   1.txt   1.txt
2.txt   3.txt   3.txt
5.txt   4.txt   5.txt
6.txt   7.txt   8.txt

Another question on my mind is how can I find the files in dir1 but not in dir2 or dir3 in a single command?

Solution 1:

diff -r dir1 dir2 | grep dir1 | awk '{print $4}' > difference1.txt

Explanation:

• diff -r dir1 dir2 shows which files are only in dir1 and those only in dir2 and also the changes of the files present in both directories if any.

• diff -r dir1 dir2 | grep dir1 shows which files are only in dir1

• awk to print only filename.

Solution 2:

This should do the job:

diff -rq dir1 dir2

Options explained (via diff(1) man page):

• -r - Recursively compare any subdirectories found.
• -q - Output only whether files differ.