Setting up the environment:
Identify remote depot and conversion directory

Identify a remote Subversion depot you wish to synchronize with. The freebsd repository is at http://svn.freebsd.org/base. I am using /Users/nmorse/freebsd for the conversion directory.

Make sure subversion is set up on your system by running these commands:
$ svnadmin --version
$ svn --version

If you don't have it, download and install it from www.collab.net/downloads/subversion/

Get a copy of p4convert-svn.jar into your conversion directory:

Make sure java 1.6 is installed
$ java -version

Make sure p4perl is installed with the Getopt extensions
$ perl -MP4 -e "print P4::Identify()"

You'll need some additional scripts:
   lockNrun.sh
   
You'll need a "lockrun" binary on your path
    I've included "lockrun.c" which will need to be compiled for your OS.


Create and initialize a "clone" of the remote svn repository

I recommend using the "svnsync" utility to clone the remote svn repository locally.
It is possible to use rsvndump but it is hideously slow, so I recommend svnsync now.

    svnadmin create svndepot
    cd svndepot/hooks
    cp pre-revprop-change.tmpl pre-revprop-change

    svnsync needs special permissions to run, edit pre-revprop-change , changing the last few lines from:

    if [ "$ACTION" = "M" -a "$PROPNAME" = "svn:log" ]; then exit 0; fi
    echo "Changing revision properties other than svn:log is prohibited" >&2
    exit 1

    to

    if [ "$USER" = "svnsync" ]; then exit 0; fi
    echo "Only the svnsync user can change revprops" >&2
    exit 1

    chmod +x pre-revprop-change
    cd ../..
    svnsync init --username svnsync file:///Users/nmorse/freebsd/svndepot http://svn.freebsd.org/base
    You will see a response like:  "Copied properties for revision 0"

Create a perforce environment on localhost

    Create a perforce server, Remember the port you specified.  The server must start empty.
    Create a perforce workspace in ./p4_client
    In ./p4_client make sure that you can access the new perforce server from the command line by setting 
        a $P4CONFIG environment variable and creating a P4CONFIG settings file, mine looks like this:

    P4USER=perforce
    P4CLIENT=svn-client
    P4PORT=4446

Configure your scripts

Edit cron-p4import.pl,  Look for "my $cvtRoot = 'path' and make sure it contains the full path to your conversion directory, like this:

my $cvtRoot        = '/Users/nmorse/freebsd';

The $batchSize and $timeout variables may also be modified to change the desired "chunk size" for each time the cron job runs.  
A bigger chunk size will import faster, but hog more system resources.

Customize your converter configuration file
Edit config.txt and make sure the following entries are correct for your choice of perforce server port and conversion directory. 
The order of entries in the config file is not important except that the last two entries 
(com.p4convert.svn.start and com.p4convert.svn.end) need to remain at the end of the file.

  com.p4convert.p4.port=localhost\:4446
  com.p4convert.p4.clientRoot=/Users/nmorse/freebsd/p4_client/
  com.p4convert.log.out.filename=/Users/nmorse/freebsd/logger.txt
  com.p4convert.svn.avd.p4root=/Users/nmorse/freebsd/p4_client/

You will also want to edit "crontab.src" to set the path and frequency with which the
converter will be called.

Controlling the conversion

On ubuntu, you can manage this script using cron 

    crontab -l             Show existing crontab entries
    crontab crontab.src    Set up a cron job
    crontab -r             Remove a crontab entry

Files generated by the conversion

    logger.txt - verbose output from the cron job
    convert.log - output from the converter
    changeMap.txt - A table mapping Subversion revisions to Perforce change IDs
    audit.log - A log of each file converted, used for validation
    current.dump - A partial subversion dump file, generated for use by the converter
    lock.lockrun - A lock file to prevent concurrent execution of the converter

Bugs and Problems
1. Be consistent about which user runs the conversion (manually and from cron)  
   if a bunch of files get written by root, you will not be able to run again as a non-privileged user.

Feedback:

There are few things which would be really useful and easy to add:

1. configurable sleep time to prevent next job to start immediately

2. E-mail report in case of the failure

3. Lock file (separate from existing lockNrun) which would remain in the work
folder after crash, which would prevent cronjob from resuming work after the
failure.

I think that adding these mods will greatly improve reliability of the whole
process. If you think you can implement them, or even suggest where to add them,
I'd be happy to work with you on it.