I just finished some mods to the script I use when switching from one project to another. The script makes it really fast and easy to try different versions of things that are wired into the command line path. For example, switching grails versions is as simple as
use grails 1.1.1
grails run-app
Switching back again…
use grails 1.2.0
grails run-app
Three things come together to make this work.
First, I keep a directory called devtools full of different versions of tools. Like this…
~/devtools/
ant/
ant-1.7.0/
ant-1.7.1/
current -> ant-1.7.1
jdk/
jdk-1.3.1/
jdk-1.4.2/
jdk-1.5.0/
jdk-1.6.0/
current -> jdk-1.5.0
grails/
grails-1.1.1/
grails-1.2.0/
current -> grails-1.1.1
...
and so on. I keep this in my home directory so it is easy for me to replicate across machines. You might want to keep it in some system specific location; like /usr/local.
Second, in my .profile I set up a bunch of environment variables to point to the current symlinks (for example: export GRAILS_HOME=~/devtools/grails/current). Also in .profile, my path is configured to include GRAILS_HOME/bin.
And third, the use script (see below) sets the current symbolic links.
With these three things in place I can quickly switch between projects with aliases that call the use script. For example…
alias iaap="use jdk 1.5.0; use grails 1.1.1; cd ~/opi/clients/mdh/iaap"
alias buyer="use jdk 1.6.0; use grails 1.2.0; cd ~/opi/clients/buyer"
...
There have got to be a million ways to do this kind of thing, but with this script I can try out different versions of things really fast. And it is especially useful when I have to go back and pick up an old project for doing a demo, debugging or whatever.
[Note: This works great for me on macosx/linux/unix though I am not sure how well it’ll fly with cygwin; don’t don’t know how well symbolic links work on windows (ln -s.)]
The use script:
#!/bin/sh
#
\# sets a symlink by convention...
#
\# For example,
\# in a directory names ~/devtools/grails with
\# ~/devtools/grails/grails-1.1.2 and
\# ~/devtools/grails/grails-1.2,
\# executing `use 1.2`
\# will create a symlink ~/devtools/grails/current -> ~/devtools/grails/grails-1.2
#
\# Set your path to include DEFAULT_TOOL_DIR/grails/current/bin. Got it?
#
USAGE="
USAGE: `basename $0`: must specify version (and optional component name.)n
USAGE: For example: `basename $0` [component] version
"
echo
DEFAULT_TOOL_DIR=~/devtools
if [ $# -eq 2 ]; then
COMPONENT=$1
VERSION=$2
echo "default_tool_dir = $DEFAULT_TOOL_DIR"
cd $DEFAULT_TOOL_DIR/$COMPONENT
elif [ $# -eq 1 ]; then
COMPONENT=`basename $PWD`
VERSION=$1
else
echo $USAGE
exit -1
fi
USE=$COMPONENT-$VERSION
if [ -d $USE ]; then
if [ -h current ]; then
CURRENT=`ls -l current | awk '{ print $11 }'`
if [ "$CURRENT" = "$USE" ]; then
echo "keeping $CURRENT"
else
echo "switching from $CURRENT to $USE"
rm current
ln -s $USE current
ls -l current | awk '{ printf "%s %s %s", $9, $10, $11 }'
echo
fi
else
echo "using $USE"
ln -s $USE current
ls -l current | awk '{ printf "%s %s %s", $9, $10, $11 }'
echo
fi
else
echo "ERROR: missing directory for $@"
if [ -h current ]; then
CURRENT=`ls -l current | awk '{ print $11 }'`
echo "WARNING: keeping $CURRENT"
else
echo "WARNING: current not set."
fi
echo $USAGE
exit -1
fi
