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Update svn working copy from folder.

Project description

Scunch updates a work copy of a source code management (SCM) system from an external folder and copies, adds and removes files and folders as necessary.

Intended scenarios of use are:

  • Automatic version management of external sources delivered by a third party.

  • Automatic version management of typically unversioned centralized resources such as server configuration files.

  • Migration of projects using folder based version management to a proper SCM.

Main features are:

  • Flexible command line interface for easy automation.

  • Support for ant patterns to specify the files to be processed.

  • Optional conversion of text files to ensure consistency and save storage space.

  • Optional transformation of file names to lower case to prevent issues with case sensitive repositories and case insensitive file systems.

  • Optional actions to be taken before and after updating the work copy to ensure consistency and prevent pending changes.

Currently supported SCM systems are:

  • Subversion (svn)

The name “scunch” is a combination of the acronym “SCM” and the word “punch” with letters removed to make it easy to pronounce. (The initial name used during early development was “scmpunch”).


To install scunch, you need:

Then you can simply run:

$ easy_install scunch

If you prefer a manual installation, you can obtain the ZIP archive from <>. Furthermore the source code is available from <>.

To actually use scunch, you also need an SCM tool. In particular, you need the SCM’s command line client to be installed and located in the shell’s search path. Installing a desktop plug-in such as TortoiseSVN is not enough because it does not install a command line client.

Here are some hints to install a command line client on popular platforms:

  • Mac OS X: svn is included in Leopard. Alternatively you can use MacPorts.

  • Linux: Use your package manager, for example: apt-get install subversion.

  • Windows: Use SlikSVN.


This section gives a short description of the available command line options together with simple examples.

To read a summary of the available options, run:

$ scunch --help

For more detailed usage in real world scenarios, read the section on scenarios.

Basic usage

To “punch” the folder /tmp/ohsome into the work copy ~/projects/ohsome, run:

$ scunch /tmp/ohsome ~/projects/ohsome

To do the same but also commit the changes, run:

$ scunch --after=commit --message "Punched version 1.3.8." /tmp/ohsome ~/projects/ohsome

Controlling the output

To control how much details you can see during the punching, use --log.. To see only warnings and errors, use:

$ scunch --log=warning /tmp/ohsome ~/projects/ohsome

To see a lot of details about the inner workings, use:

$ scunch --log=debug /tmp/ohsome ~/projects/ohsome

Possible values for --log are: debug, info (the default), warning and error.

Specifying which files to process

By default, scunch considers almost all files and folders in the external folder for transfer, excluding:

  • internal files and folders used by popular SCM systems, for example .svn and .gitignore.

  • internal system files, for example MacOS X’s .DS_Store.

  • apparent temporary files, for example #*#.

To ignore additional files use --exclude=PATTERN with PATTERN using the popular ant pattern syntax. Ant patters are similar to shell patterns and support the “*” and “?” place holder as usual. In addition to that, “**” stands for any amount of folders and sub folders matching any folder nesting level.

For example, to exclude all Python byte code files, use:

$ scunch --exclude "**/*.pyc, **/*.pyo" ...

In case you want to punch only Python and files and ignore everything else, use --include:

$ scunch --include "**/*.py" ...

Of course you can combine both options to for example punch all Python files except test cases:

$ scunch --include "**/*.py" --exclude "**/test_*.py" ...

Sometimes the work copy includes files that will never exist in the external folder. For example, the work copy might contain a script to run scunch with all options set up already. Because this script does not exist in the external folder, it would be removed as soon as scunch is run. To prevent this from happening, use --work-only=PATTERN. For example:

$ scunch --work-only "" ...

Note that this example does not use the “**” place holder because only files in the work copy’s top folder are of interest.

Preparing the work copy

When punching any changes from the external folder the current state of the work copy influences what actually is going to happen.

Scunch works best on a clean work copy without any pending changes and messed up files. If this is not the case, scunch refuses to continue announcing:

Pending changes in “…” must be committed, use “svn status” for details. To resolve this, use ‘–before=reset’ to discard the changes or ‘–before=none’ to ignore them.

In case you are sure the changes are irrelvant and intend to discard them, use:

$ scunch --before reset ...

This reverts all changes and removes files not under version control.

In case you prefer a clean check out, use:

$ scunch --before checkout --depot ...

where represents the project’s depot qualifier. Note that a before=checkout usually takes longer than a --before=reset because a checkout needs to obtain all files again where else a --before=checkout needs to obtain every file in the depot.

In case you are happy with the current pending changes and want to preserve them even after punching the external changes, use:

$ scunch --before none ...

The result might or might not be what you want, though.

Committing punched changes

To automatically commit the changes scunch just punched into your work copy, use:

$ scunch --after commit ...

To do the same with a meaningful log message, use:

$ scunch --after commit --message "Punched version 1.3.8." ...

In case you use a script to launch scunch and want to get rid of the work copy once it is done, you can specify multiple actions for --after separated by a comma:

$ scunch --after "commit, purge" ...

The actions are performed in the given order so make sure to use purge last. Also notice the double quotes (”) around "commit, purge". They ensure that the shell does not consider purge a command line option of its own.

Moving or renaming files

By default, scunch checks for files added and removed with the same name but located in a different folder. For example:

Added  : source/tools/
Removed: source/

With Subversion, scunch will internally run:

$ svn move ... source/ source/tools

instead of:

$ svn add ... source/tools/
$ svn remove ... source/

The advantage of moving files instead of adding/removing them is that the version history remains attached to the new file.

Note that this only works for files but not for folders. Furthermore, the file names must be identical including upper/lower case and suffix.

If you rather want to add/remove files instead of moving them, you can specify the move mode using the --move=MODE:

$ scunch --move=none /tmp/ohsome ~/projects/ohsome

Possible move modes are:

  • name (the default): move files with identical names.

  • none: use add/remove instead if move.

Transforming names

Especially when punching sources from 3rd parties sometimes some letters of file or folder names change from lower case to upper case or the other way around. For example, a file called some.txt might be named Some.txt the next time around.

On a case sensitive file system (for instance most Unix file systems), this result in the SCM to not make the connection between the two files and starting a new change history. On a case insensitive file system (such as the standard file systems for Mac OS X and Windows), the SCM gets seriously confused because it is made to believe there are to files but the file system can only store one of them at a time.

In order to prevent this, you can tell scunch to transform names of files and folders while punching them into a work copy. For example:

$ scunch --names=lower ...

This converts all names to lower case.

Possible values for --names are:

  • preserve (the default): keep names as the are

  • lower: transform names to lower case; for example, Some.txt becomes some.txt.

  • upper: transform names to upper case; for example, Some.txt becomes SOME.TXT.

Note that you should specify --names the first time when starting with a new work copy. Renaming existing files and folder by only changing the case of letters confuses most SCM’s when the work copy resides on a case insensitive file system.

Dealing with non ASCII file names

To perform SCM operations, scunch simply runs the proper SCM command line client as a shell process in the background. This typically works nice and dandy as long as all files to be processed have names that solely consist of ASCII characters. As soon as you have names in Kanji or with Umlauts, trouble can ensue.

By default, scunch attempts to figure out proper settings for such a situation by itself. However, this might fail and the result typically is a UnicodeEncodeError.

The first sign of trouble is when scunch logs the following warning message:

LC_CTYPE should be set to for example ‘UTF-8’ to allow processing of file names with non-ASCII characters

This indicates that the console encoding is set to ASCII and any non ASCII characters in file names will result in a UnicodeEncodeError. To fix this, you can tell the console the file name encoding by setting the environment variable LC_CTYPE. For Mac OS X and most modern Linux systems, the following command should do the trick:

$ export LC_CTYPE=UTF-8

For Windows 7 you can use:

> set LC_CTYPE=UTF-8

Note that this can have implications for other command line utilities, so making this a permanent setting in .profile or .bashrc might not be a good idea. Alternatively you can specify the proper encoding every time you run scunch (upper/lower case does not matter here):

$ scunch --encoding=utf-8 /tmp/ohsome ~/projects/ohsome

For other platforms, you can try the values above. If they do not work as intended, you need to dive into the documentation of your file system and find out which encoding it uses.

But even if the encoding is correct, scunch and the file system still might disagree on how to normalize Unicode characters. Again, scunch attempts to figure out the proper normalization but in case it is wrong you can specify it using --normalize. Possible value are: auto (the default), nfc, nfkc, nfd and nfkd. To understand the meaning of these values, check the Unicode Consortium’s FAQ on normalization.

As a complete example, the proper options for Mac OS X with a HFS volume are:

$ scunch --encoding=utf-8 --normalize=nfd /tmp/ohsome ~/projects/ohsome

Incidentally, these are the values scunch would have used already, so in practice there is not need to explicitly state them.

If however the files reside on a UDF volume, the proper settings would be:

$ scunch --normalize=nfc /tmp/ohsome ~/projects/ohsome

In case the external files to punch into the work copy reside on a volume with different settings than the work copy, or you cannot figure them out at all, try to copy the files to a Volume with know settings and run scunch on this copy.


This section describes common scenarios where scunch can be put to good use.

Upgrading from old school version management

Tim is a hobbyist developer who has been programming a nifty utility program for a while called “nifti”. Until recently he has not been using any version management. If he deemed it useful to keep a certain state of the source code, he just copied it to a new folder and added a timestamp to the folder name:

$ cd ~/projects
$ ls

After having been enlightened, he decides to move the project to a Subversion repository. Nevertheless he would like to have all his snapshots available.

As a first step, Tim creates a local Subversion repository:

$ mkdir /Users/tim/repositories
$ svnadmin create /Users/tim/repositories/nifti

Next he adds the project folders using the file protocol:

$ svn mkdir file:///Users/tim/repositories/nifti/trunk  file:///Users/tim/repositories/nifti/tags  file:///Users/tim/repositories/nifti/branches

No he can check out the trunk to a temporary folder:

$ cd /tmp
$ svn checkout --username tim file:///Users/tim/repositories/nifti/trunk nifti

Now it is time to punch the oldest version into the still empty work copy:

$ cd /tmp/nifti
$ scunch ~/projects/nifti_2010-05-23

Tim reviews the changes to be committed. Unsurprisingly, there are only “add” operations:

$ svn status
A   README.txt
A   nifti/

To commit this, Tim runs:

$ svn commit --message "Added initial version."

Then he proceeds with the other versions, where he lets scunch handle the commit all by itself:

$ scunch --commit ~/projects/nifti_2010-07-03
$ scunch --commit ~/projects/nifti_2010-08-18
$ scunch --commit ~/projects/nifti_2010-11-27
$ scunch --commit ~/projects/nifti

Now all the changes are nicely traceable in the repository. However, the timestamps use the time of the commit instead of the date when the source code was current. In order to fix that, Tim looks at the history log to find out the revision number of his changes and notes which actual date the are supposed to represent:

r1 --> before 2010-05-23
r2 --> 2010-05-23
r3 --> 2010-07-03
r4 --> 2010-08-18
r5 --> 2010-11-27
r6 --> today

To update the timestamp in the repository, Tim sets the revision property date accordingly:

$ svn propset svn:date --revprop --revision 2 "2010-05-23 12:00:00Z" file:///Users/tim/repositories/nifti/trunk

Note that this only works with the file protocol. If you want to do the same on a repository using the http protocol, you have to install a proper post commit hook in the repository that allows you to change properties even after they have been committed. Refer to the Subversion manual for details on how to do that.

Similarly, Tim can set the log comments to a more meaningful text using the revision property log.

Once the repository is in shape, Tim can remove his current source code and replace it with the work copy:

$ cd ~/projects
$ mv nifti nifti_backup # Do not delete just yet in case something went wrong.
$ svn checkout file:///Users/tim/repositories/nifti/trunk nifti

Now Tim has a version controlled project where he can commit changes any time he wants.

Version management of third party source code

Joe works in an IT department. One of his responsibilities to install updates for a web application named “ohsome” developed and delivered by a third party. The work flow for this is well defined:

  1. Vendor send the updated source code to Joe in a ZIP archive containing a mix of HTML, JavaScript and XML files, mixed in with a few server configuration files.

  2. Joe extracts the ZIP archive to a local folder.

  3. Joe moves the contents of local folder to the application folder on the server. In the process, he removes all previous files for the application.

This works well as long as the vendor managed to pack everything into the ZIP archive. However, experience shows that the vendor sometimes forgets to include necessary files in the ZIP archive or does include configurations files intended for a different site. While these situations always could be resolved, it took a long time to analyze what’s wrong and find out which files were effected. This resulted in delays of a release, reduced end user satisfaction and large amount of phone calls being made and email being sent - including summaries for the management.

Joe decides that it would be a good idea to take a look at the changes before copying them to the web server. And even if he cannot spot a mistake before installing an update, SCM should help him in his analysis later on.

Joe’s company already has a Subversion repository for various projects, so as a first step he adds a new project to the repository and creates a new work copy on his computer:

$ svn add --message "Added project folders for ohsome application by Vendor."

This creates a project folder and the usual trunk, tags and branches folders. For the time being, Joe intends to use only the trunk to hold the most current version of the “ohsome” application.

Next, Joe creates a yet empty work copy in a local folder on his computer:

$ cd ~/projects
$ svn checkout ohsome

Now he copies all the files from the web server to the work copy:

$ cp -r /web/ohsome/* ~/projects/ohsome

Although the files are now in the work copy, the are not yet under version management. So Joe adds almost all the files except one folder named “temp” that according to his knowledge contains only temporary files generated by the web application:

$ cd ~/projects/ohsome
$ svn propset svn:ignore temp .
$ svn add ...

After that, he manually commits the current state of the web server:

$ svn commit --message "Added initial application version 1.3.7."

For the time being, Joe is done.

A couple of weeks later, the vendor send a ZIP archive with the application version 1.3.8. As usual, Joe extracts the archive:

$ cd /tmp
$ unzip ~/Downloads/

The result of this is a folder /tmp/ohsome containing all the files and folders to be copied to the web server under /web/ohsome/. However, this time Joe wants to review the changes first by “punching” them into his work copy. So he runs scunch with the following options:

$ scunch /tmp/ohsome ~/projects/ohsome

This “punches” all the changes from folder /tmp/ohsome (where the ZIP archive got extracted) to the work copy in ~/projects/ohsome.

As a result Joe can review the changes. He uses TortoiseSVN for that, but svn status and svn diff would have worked too.

Once he finished his review without noticing any obvious issues, he manually commits the changes:

$ cd ~/projects/ohsome
$ svn commit --message "Punched version 1.3.8."

When version 1.3.9 ships, Joe decides that he might as well review the changes directly in the repository after the commit. So this time he simply uses:

$ cd /tmp
$ unzip ~/Downloads/
$ scunch --commit --message "Punched version 1.3.9."

Joe can then use svn log to look for particular points of interest. For instance, to find modified configuration files (matching the pattern *.cfg):

$ svn log --verbose --limit 1 | grep "\.cfg$"

To get a list of Removed files and folders:

$ svn log --verbose --limit 1 | grep "^   D"

(Note: Here, grep looks for three blanks and a “D” for “deleted” at the beginning of a line.)


Copyright (C) 2011 - 2012 Thomas Aglassinger

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this program. If not, see <>.

Version history

Version 0.5.8, 2012-05-08

  • #21: Fixed adding of files within 3 nested otherwise empty folders.

  • Improved debug logging for ant patters: it can now be set separately by using logger ‘antglob.pattern’.

Version 0.5.7, 2012-04-08

  • Fixed confusing warning message in case LC_CTYPE was not set properly.

  • Fixed logging messages which can now handle non ASCII paths properly.

  • Improved performance by changing some lists to sets.

Version 0.5.6, 2011-03-04

  • #20: Changed --names to fail in case the work copy already contains existing entries not complying to the name transformation.

  • Changed file attributes of transferred text files to use the same attributes as the source file.

Version 0.5.5, 2011-02-28

  • Fixed --before=reset, which did not remove unversioned added folders.

  • Cleaned up code.

Version 0.5.4, 2011-02-23

  • Improved validation of command line options.

  • Cleaned up error messages, code and documentation.

Version 0.5.3, 2011-02-20

  • #18: Added transformations of file and folder names, use for example --names=lower.

  • #19: Fixed duplicate processing of punched folders in root folder.

Version 0.5.2, 2011-02-17

  • #16: Fixed moving of files in moved folders, during which the containing folder was removed before the files could be moved.

  • #14: Fixed logged numbers of files processed.

  • #15: Added list of possible values to --help for options of type choice.

Version 0.5.1, 2011-02-14

  • #10: Added command line option --before to specify action to be taken before punching.

  • Added check that no changes are pending before copying files from the external folder. Use --before=none to skip this.

  • #11: Added command line option --after to specify actions to be taken after punching.

  • Removed command line option --commit, use --after=commit instead.

Version 0.5.0, 2011-02-12

  • #12: Added options --include and --exclude to specify which files in the external folder should be punched. These options take a list of ant patterns separated by a comma (,) or blank space.

  • #13: Added option --work-only to specify files and folders that only exist in the work copy but not in the external folder but should be preserved nevertheless. This is useful if the work copy contains helper scripts, build.xml for ant, Makefiles and so on that call scunch or other tools but will never be part of the external folder.

  • Changed --text to use ant-like pattern instead of a suffix list. For example now use --text="**/*.txt" instead of ``text=txt.

Version 0.4.1, 2011-01-09

  • Fixed AssertionError if no explicit --encoding was specified.

  • Cleaned up command line help and code.

Version 0.4, 2011-01-08

Added options to normalize text files and fixed some critical bugs.

  • #4: Added command line option --text to specify which files should be considered text and normalized concerning end of line characters.

  • #5: Added command line option --newline to specify which end of line characters should be used for text files.

  • #6: Added command line option --tabsize to specify that tabs should be aligned on a certain number of spaces in text files.

  • #7: Added command line option --strip-trailing to remove trailing white space in text files.

  • Fixed sorting of file names which could result into inconsistent work copies.

  • Fixed processing of internal file name diff sequences of type ‘replace’, which could result in inconsistent work copies.

Version 0.3, 2011-01-05

  • Fixed processing of file names with non ASCII characters for Mac OS X and possibly other platforms.

  • Added command lines options --encoding and --normalize to specify how to deal with non ASCII characters.

Version 0.2, 2011-01-04

  • Fixed NotImplementedError.

  • Added support for moving files with same name instead of performing a simple add/remove. This preserves the version history on the new file. Use --move=none to get the old behavior.

  • Cleaned up logging output.

Version 0.1, 2011-01-03

  • Initial release.

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