Check if the contents of the x.txt file under a particular directory is the same as the x.txt file content in other directories, bash conditional

Question

I have tree folders folder-1,folder-2 and folder-3 located both in my /home/.

folder-1 contains x.txt, but folder-2 contains files x.txt, y.txt, z.txt, etc.

folder-3 contains contains files x.txt, y.txt, z.txt, etc.

Only /home/folder-2/x.txt has the same content as /home/folder-1/x.txt.

/home/folder-2/x.txt do not have the same content that folder /home/folder-1/x.txt.

I know if I want to compare "content" (and not the size or name) of two files in different folders I can use:

a="/home/folder-1/x.txt"
b="/home/folder-2/x.txt"

if cmp -s "$a" "$b"; then
    printf 'A file with duplicate content found'
else
    printf 'No file with duplicate content found'
fi

But this is not something practical and efficient when I have a single file and your content to compare with files from anothers folders that has many files.

I researched a way to adapt my code write another conditional bash so that I can compare /home/folder-1/x.txt with all existing files in /home/folder-2/{all files} and /home/folder-3/{all files}.

I necessarily need to write this using conditional bash, as if there is a file "x.txt" on the folder-2 and folder-3 with the same content that x.txt then I will shoot a new command, action or decision.

But so far I have not found anything that can help me concretely.

Note: folder-2 and folder-3 has no subdirectories.

Answer 1

Use a for loop.

file1=/home/folder-1/x.txt
dupfound=
for file2 in /home/folder-2/* /home/folder-3/*
do
    if cmp -s "$file1" "$file2"
    then 
        printf 'Duplicate found: %s\n' "$file2"
        dupfound=true
    fi
done
if [ -z "$dupfound" ]
then "No duplicate found"
fi