find: Finding the Shallowest Instance
10.4 Finding the Shallowest Instance
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Suppose you maintain local copies of sources from various projects, each
with their own choice of directory organisation and source code
management (SCM) tool. You need to periodically synchronize each
project with its upstream tree. As the number local repositories grows,
so does the work involved in maintaining synchronization. SCM utilities
typically create some sort of administrative directory: .svn for
Subversion, CVS for CVS, and so on. These directories can be used as a
key to search for the bases of the project source trees. Suppose we
have the following directory structure:
repo/project1/CVS
repo/gnu/project2/.svn
repo/gnu/project3/.svn
repo/gnu/project3/src/.svn
repo/gnu/project3/doc/.svn
repo/project4/.git
One would expect to update each of the 'projectX' directories, but
not their subdirectories (src, doc, etc.). To locate the project roots,
we would need to find the least deeply nested directories containing an
SCM-related subdirectory. The following command discovers those roots
efficiently. It is efficient because it avoids searching subdirectories
inside projects whose SCM directory we already found.
find repo/ \
-exec test -d {}/.svn \; -or \
-exec test -d {}/.git \; -or \
-exec test -d {}/CVS \; -print -prune
In this example, 'test' is used to tell if we are currently examining
a directory which appears to the a project's root directory (because it
has an SCM subdirectory). When we find a project root, there is no need
to search inside it, and '-prune' makes sure that we descend no further.
For large, complex trees like the Linux kernel, this will prevent
searching a large portion of the structure, saving a good deal of time.
Info Catalog
find: Updating A Timestamp File
find: Worked Examples