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a tool for code clone detection

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dupl is a tool written in Go for finding code clones. So far it can find clones only in the Go source files. The method uses suffix tree for serialized ASTs. It ignores values of AST nodes. It just operates with their types (e.g.

if a == 13 {}
if x == 100 {}
are considered the same provided it exceeds the minimal token sequence size).

Due to the used method dupl can report so called "false positives" on the output. These are the ones we do not consider clones (whether they are too small, or the values of the matched tokens are completely different).


go get -u


Usage of dupl:
  dupl [flags] [paths]

Paths: If the given path is a file, dupl will use it regardless of the file extension. If it is a directory it will recursively search for *.go files in that directory.

If no path is given dupl will recursively search for *.go files in the current directory.

Flags: -files read file names from stdin one at each line -html output the results as HTML, including duplicate code fragments -plumbing plumbing (easy-to-parse) output for consumption by scripts or tools -t, -threshold size minimum token sequence size as a clone (default 15) -vendor check files in vendor directory -v, -verbose explain what is being done

Examples: dupl -t 100 Search clones in the current directory of size at least 100 tokens. dupl $(find app/ -name '_test.go') Search for clones in tests in the app directory. find app/ -name '_test.go' |dupl -files The same as above.


The reduced output of this command with the following parameters for the Docker source code looks like this.

$ dupl -t 200 -html >docker.html

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