linux - The diff command for files with empty content -

if want difference between 2 directories, use command below:

diff -arun dir1/ dir2/ > dir.patch

so dir.patch file should comprise differences want, right?

but if dir2/ contains file empty content, , file not existent in dir1/, example,

dir1/  dir2/empty_content_file.txt ------ empty content.

then diff command not generate patch empty_content_file.txt, needed file.

is there expertise or alternative way this?

thank in advance.

it's because you're using -n option, added explicitly treat absent file empty. man diff says :

     -n,  --new-file                treat absent file empty

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