Skip to the content.

Find patterns in paths

path-pattern finder is a Java library to find naming-patterns in a list of strings or paths, using a particular set of rules. A command-line app for basic usage is also included.

One can translate a set of file-paths into their constant and non-constant (variable) components.

e.g. consider some paths


In this case, the library would find the pattern:


where {0} indexes each component.


Consider a directory of picture files (with several nested sub-directories).

Files take the form:

C:\Users\Owen\Pictures\Holidays\Italy at Easter (March 2013)\Milan\2013-04-02 20.07.42.jpg
C:\Users\Owen\Pictures\Holidays\Italy at Easter (March 2013)\Milan\IMG_4677.JPG
C:\Users\Owen\Pictures\Holidays\Italy at Easter (March 2013)\Milan\IMG_4678.JPG
C:\Users\Owen\Pictures\Holidays\Italy at Easter (March 2013)\Milan\IMG_4682.JPG
C:\Users\Owen\Pictures\Holidays\Italy at Easter (March 2013)\Verona\IMG_4252.JPG
C:\Users\Owen\Pictures\Holidays\Italy at Easter (March 2013)\Verona\IMG_4255.JPG
C:\Users\Owen\Pictures\Holidays\Italy at Easter (March 2013)\Verona\IMG_4261.JPG

The command-line app would produce:

There are 274 input paths in total

Pattern is: C:\Users\Owen\Pictures\Archived\Holidays\Italy at Easter (March 2013)\${0}\${1}${2}.jpg

${0} = 6 unique strings e.g. "Venice" (145), "Milan" (38), "Verona" (34)
${1} = "IMG_" (273) | "2013-04-02 20.07." (1)
${2} = 274 unique integers between 42 and 4766 inclusive

The number in parantheses describes the number of files in a particular category.


The latest JARs are stored in Maven Central.


If not using maven, a tar.gz distribution (that contains a Windows launcher binary, and a Linux launcher script) can be downloaded from GitHub.


Either as a Java library, or a command-line tool.

Being pure Java, it works on Windows, Linux, Mac and several other operating systems.

An .exe launcher and Linux wrapper-script are included in the distribution for easy command-line use in Windows and Linux.

After unpacking the zip/tar.gz distribution, it is advisable to add the bin/ directory to the system path.

…as a command-line app

Call path-pattern-finder as an application with one or more wildcard arguments e.g.

path-pattern-finder *.jpg *.png

This will

  1. recursively search the current working directory for files matching the wildcard arguments (a glob)
  2. find the pattern
  3. print the pattern to the console

…as a library

Use the methods in PathPatternFinder to find patterns. e.g. findPatternPaths or findPatternStrings.

import com.owenfeehan.pathpatternfinder.PathPatternFinder;
Pattern pattern = PathPatternFinder.findPatternPaths(paths, IOCase.INSENSITIVE, true);

Or to find the common root-directories of a list of paths, see FindCommonPathElements.

import com.owenfeehan.pathpatternfinder.commonpath.FindCommonPathElements;
Optional<Path> commonPath = FindCommonPathElements.findForFilePaths(paths);

See the Javadoc for more detailed code documentation.



Source code can be found on GitHub, together with artifacts and continuous integration. Code quality metrics are found on SonarCloud.


Owen Feehan distributed under MIT license.