This document is not intended to be a full guide to using SVN effectively. It should, however, be a sufficient introduction for how you’ll be using it in CS 225 (and future CS/ECE courses).
For more information:
svn help to view SVN’s built-in documentation.Subversion will be used throughout this semester as the version control system for MPs and labs. Specifically, we will be using SVN for two functions:
While we do not require that you learn and use good version control practices, we cannot stress enough how useful a good version control system can be when good practices are used. The following is a brief list of good version control practices:
Again, the above practices are not hard and fast, nor complete, but they should help you complete your MPs and future coding projects should you use SVN for them as well.
svn helpSyntax: svn help [SUBCOMMAND]
The help command displays the internal SVN help. svn help displays an
overview of the available subcommands, and svn help SUBCOMMAND gives the help
for a particular SUBCOMMAND.
Example
To get help on the add subcommand, run:
svn help add
svn checkout (svn co)Syntax: svn checkout URL [directory]
The checkout command is used to download a copy of the repository located at
URL. If directory is given, the repository is downloaded into that
directory. By default, it is downloaded into a directory named after the last
segment of URL.
Example
To checkout this semester’s repository into a directory named cs225, run:
svn checkout https://subversion.ews.illinois.edu/svn/-cs225/NETID/ cs225
replacing NETID with your NetID.
svn update (svn up)Syntax: svn update
The update command downloads the latest revisions from the repository. Use it
to download newly released assignments or if you’ve committed on a different
machine.
Example To update your copy of the repository:
cd path/to/your/cs225/directory
svn update
svn addSyntax: svn add FILE...
The add command tells SVN to start tracking a particular file or set of
files.
Note that svn add does NOT upload files. You need to also svn
commit it.
Example
To add a file named partners.txt, run:
svn add partners.txt
svn status (svn st)Syntax: svn status
The status command displays what will be committed on the next svn
commit. It outputs a list of files, each with
a single-letter status indicator:
A file.cpp means that file.cpp has been added and will be uploaded on
with the next svn commit.M file.cpp means that file.cpp has been modified and the
modifications will be uploaded with the next svn commit.D file.cpp means that file.cpp has been deleted and the file will be
deleted with the next svn commit.? file.cpp means that file.cpp is not going to be uploaded and will be
ignored by Subversion.C file.cpp means that file.cpp is in conflict, which means that the
version on the repository and your local copy have both changed. See
Resolving Conflicts.There are other status indicators not listed here; see svn help status for
the full list.
Example To get the status of files in the current directory, run:
svn status
This may give something like
A main.cpp
M rgbapixel.cpp
? rgbapixel.h
which means:
main.cpp is a new file that is going to be committed.rgbapixel.cpp are going to be committed.rgbapixel.h is not being tracked by Subversion.svn commit (svn ci)Syntax: svn commit -m "COMMIT_MESSAGE"
The commit command is used to upload changes to the repository. A commit
message must be given. See this StackOverflow
question
for guidelines on how to write good commit messages.
svn commit will display the revision number created at the end of the commit.
If Subversion prints out errors or it doesn’t say Committed revision
REVISION_NUMBER., your commit didn’t happen.
Example To commit your changes, run:
svn commit -m "Finish main.cpp; fix a bug in rgbapixel.cpp"
which may output something like
Adding main.cpp
Sending rgbapixel.cpp
Adding rgbapixel.h
Transmitting file data ...
Committed revision 400.
which means:
main.cpp, rgbapixel.cpp, rgbapixel.h were uploadedsvn logSyntax: svn log PATH
The log command is used to view the history of a given file (or directory).
PATH can be either a local file or a URL. (To view the log for the current
directory, use svn log .)
svn log can produce a lot of output; it’s usually best to pipe it to a pager
like less:
svn log . | less
In less, use Vim keys (or the arrow keys) to navigate. Press q to
quit.
Example To view the log for the current directory, run:
svn log .
which may output something like
------------------------------------------------------------------------
r400 | netid | 2015-08-20 16:14:55 -0500 (Thu, 20 Aug 2015) | 1 line
Finish main.cpp; fix a bug in rgbapixel.cpp
------------------------------------------------------------------------
r394 | netid | 2015-08-20 15:58:03 -0500 (Thu, 20 Aug 2015) | 1 line
Implement the RGBAPixel class
------------------------------------------------------------------------
r100 | tolar2 | 2015-08-18 00:08:39 -0500 (Tue, 18 Aug 2015) | 1 line
releasing mp1
------------------------------------------------------------------------
Note that the commit messages are displayed, as well as the revision numbers, the author of the commit, and the date of the commit.
SVN can oftentimes get into a weird state, whether that be to conflicts or other reasons.
There are usually “correct” ways to solve SVN problems, but the safest and easiest is to just re-checkout your repository:
# Move your old cs225/ directory out of the way
mv -Tn cs225 cs225.old
# Re-checkout your repository
svn co https://subversion.ews.illinois.edu/svn/-cs225/NETID cs225
# Copy over any changes you made, e.g.,:
cp cs225.old/mp1/main.cpp cs225/mp1/main.cpp
If the mv command gives an error, that means that you’ve likely already done
this at some time in the past. Either delete cs225.old (after checking that
you don’t need anything in it), or pick a different name (e.g., cs225.old1).