CODEWITHSUNDEEP
bashshellintersection
Valentin Montmirail
Valentin Montmirail

Reputation: 2640

Intersection of N files

I've got a little problem in bash.

I've got N files containing filenames, and I would like to find the list of filenames which are contained in all the file (the intersection of the files).

When there is 2 files, I found this solution: sort file1 file2 | uniq -d, and this is actually doing what I want.

But how to generalize it to N files in the same folder ?

File1

    1 
    2 
    3 
    4

File2

    1 
    4

File3

    2 
    3 
    4

Output expected:

    4

Thanks in advance, Best Regards.

Upvotes: 1

Views: 414

Answers (1)

hidefromkgb
hidefromkgb

Reputation: 5903

I`m not Marc B, but still, here`s the implementation of his idea:

intersect() {
    sort "$@" | uniq -cd | grep "^[^0-9]*$# "
}

# usage example
intersect file1 file2 file3

[EDIT:] To overcome the problem of duplicate lines within the same file, I`d do something like this:

intersect() {
    for file in "$@"; do
        sort -u "$file"
    done | sort | uniq -cd | grep "^[^0-9]*$# "
}

Upvotes: 4

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