How to obtain the result of a diff between 2 files in a loop?

General Usage
4

--quiet is a GNU-ism; if you want it to work with any POSIX cmp you should use -s.

Of course, this won’t work on Windows. It would be pretty easy to write an equivalent Julia function, though, like:

function filecmp(path1::AbstractString, path2::AbstractString)
    stat1, stat2 = stat(path1), stat(path2)
    if !(isfile(stat1) && isfile(stat2)) || filesize(stat1) != filesize(stat2)
        return false # or should it throw if a file doesn't exist?
    end
    stat1 == stat2 && return true # same file
    open(path1, "r") do file1
        open(path2, "r") do file2
            buf1 = Vector{UInt8}(undef, 32768)
            buf2 = similar(buf1)
            while !eof(file1) && !eof(file2)
                n1 = readbytes!(file1, buf1)
                n2 = readbytes!(file2, buf2)
                n1 != n2 && return false
                0 != Base._memcmp(buf1, buf2, n1) && return false
            end
            return eof(file1) == eof(file2)
        end
    end
end

Not only is this more portable, it is also much faster than executing an external program like cmp. On my Mac laptop it is about 1000× faster in the common case where the file sizes differ, and about 60× faster for a 20kB file when the files match (so that the whole files need to be read).

(Python provides filecmp.cmp in its standard library, I wonder if Julia should too?)

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