unix - sort content of two folders then compare using diff command

Question

How do I sort contents of two different folders before comparing those two directories using diff?

Answer 1

You could use diff with process substitution:

diff <(ls -a dir1/) <(ls -a dir2/)

• <(...) creates a file descriptor whose path is added as argument to diff.
• When no sort option is given, ls sort the output alphabetically.
• The two ls-outputs are give to diff for comparsion.

My example folders look like this:

.
├── dir1
│   ├── file1
│   ├── file2
│   └── file3
└── dir2
    ├── file2
    ├── file3
    └── file4

The output is this case is:

$ diff <(ls -a dir1/) <(ls -a dir2/)
3d2
< file1
5a5
> file4