Linux: Bash generic script to switch versions (like alternatives and Gentoo's eselect)
2012-12-13
Linux:
Bash generic script to switch versions (like alternatives and
Gentoo's eselect)
I've made a switch script.
Usage
$ switch $ switch maven 2.2.1 $ mvn -version $ switch maven 2.1.0 $ mvn -version
Installation
It uses your ~/sw/tools/.links, so update your PATH.
export PATH=~/sw/tools/.links:$PATH
Then (optionally):
$ /mnt/jqa/sw/tools/switch.sh install Creating ~/sw/tools/.links/switch -> /mnt/jqa/sw/tools/switch.sh
Download
Download here.
Script's code
#####################################################################################################
#
# This script creates switches between the versions of various tools,
# found in /mnt/jqa/sw/tools/ (curently hard-coded).
#
# Usage:
# $ switch maven 2.1.0
# $ mvn ...
#
# Installation:
# * Set PATH to begin with ~/sw/tools/.links (in ~/.bashrc)
#
# Tools directory structure:
# * .../<tool_name>/
# * <tool_version>/
# * <tool_version2>/
# * onSwitch.sh
# * onRun.sh
#
# Callback scripts:
#
# * onSwitch.sh - called when the version switch is performed.
# * Called using: . onSwitch.sh <tool_name> <tool_version>
#
# * onRun.sh - if present, all tool's runnables will be called through a script,
# which will be re-created each time the versions are switched:
#
# TOOL_NAME=<tool_name> # Few variables are set at the top of the script.
# TOOL_VERSION=<...> # 1.2.3
# TOOL_HOME=<...> # Tool home dir - i.e., the dir particular version.
# TOOL_RUNNABLE_PATH=<...> # Path to the runnable to be called.
#
# <content of onRun.sh> # The content is simply pasted here.
# <tool_runnable> $@ # Calls the current version of the tool runnable.
#
# Todo:
# * Upon switch, remove links created with previous switch.
# * All that belong to the tools/<tool_name> dir (parse the variables at the top of the scripts)
#
# History:
# 2009-12-22:
# * Runnables are now searched automatically in TOOL_HOME/bin if there's no runnables.txt.
# * Softlinks to executable files also count as runnables.
# * Home dir of this script is detected automatically.
# * Meta-dirs now start with a dot (.links, .homes, .template).
#
#
#####################################################################################################
##
## @param $1 Tool name
## @param $2 Tool version
## @param $3 Tool runnable path
## @param $4 TOOL_HOME - path to the home dir of the selected version of the tool.
## @param $5 ON_RUN - a script to execute before the runnable is run.
##
function createRunnableScript {
TOOL_RUNNABLE_PATH=$3
TOOL_HOME=$4
ON_RUN=$5
TOOL_RUNNABLE_NAME=`basename $TOOL_RUNNABLE_PATH`;
MY_LINK=~/sw/tools/.links/$TOOL_RUNNABLE_NAME
if [ -e "$MY_LINK" ] ; then rm $MY_LINK; fi
if [ -z "$ON_RUN" ] ; then
echo "Creating link $MY_LINK -> $TOOL_RUNNABLE_PATH"
ln -s $TOOL_RUNNABLE_PATH $MY_LINK
else
echo "Creating bash script: $MY_LINK"
echo "TOOL_NAME=$1" > $MY_LINK;
echo "TOOL_VERSION=$2" >> $MY_LINK;
echo "TOOL_HOME=$TOOL_HOME" >> $MY_LINK;
echo "TOOL_RUNNABLE_PATH=$TOOL_RUNNABLE_PATH" >> $MY_LINK;
cat $ON_RUN >> $MY_LINK;
echo "" >> $MY_LINK
echo "exec $TOOL_RUNNABLE_PATH \"\$@\"" >> $MY_LINK;
fi
chmod +x $MY_LINK
}
## Return value.
RET=0
## Determine this script's location ("Tools" home dir).
#TOOLS="/home/ondra/sw/tools"
#scriptPath=$(cd ${0%/*} && echo $PWD/${0##*/})
scriptPath="$(cd "${0%/*}" 2>/dev/null; echo "$PWD"/"${0##*/}")"
# For the case when called through a symlink (eg. sw/tools/.links/switch -> ../switch.sh).
scriptPath=`readlink -f "$scriptPath"`
TOOLS=`dirname "$scriptPath"`
## Install - create the .links dir and a link to the switch.sh script.
## Assumes that user will put ~/sw/tools/.links at the beginning of his $PATH.
if [ "$1" == "install" ] ; then
if [ ! -x ~/sw/tools/.links/switch ] ; then
echo "Creating ~/sw/tools/.links/switch -> $scriptPath"
mkdir -p ~/sw/tools/.links
ln -s $scriptPath ~/sw/tools/.links/switch
else
echo "~/sw/tools/.links/switch already exists."
fi
exit;
fi
while true; do
if [ "on" == "$1" ] ; then
## No way to export a variable without sourcing this script :(
export PATH=~/sw/tools/.links:$PATH
fi
## No arguments: List available tools and versions.
if [ -z "$1" -o -z "$2" ] ; then
echo " Usage: switch <tool> <ver>";
echo " Available tools and versions:"
for TOOL in `ls -1 --ignore=switch.* --ignore=.* --ignore=_* $TOOLS`; do
if [ ! -d "$TOOLS/$TOOL" ] ; then continue; fi
#echo " $TOOL `ls --ignore=*.path $TOOLS/$TOOL`";
echo " "$(echo "$TOOL `find -L $TOOLS/$TOOL/ -mindepth 1 -maxdepth 1 -type d | sed 's#.*/##'`");
#tree -diL 1
#ls -l | grep ^d | awk '{print $9}'
done
break;
fi
## Has to be sourced for it sets variables into the environment (like M2_HOME).
if [ "$0" == "switch.sh" ] ; then
echo "This file (switch.sh) has to be source'd ('. switch.sh').";
exit 666;
fi
## Tool's root dir (contains dirs with concrete versions).
TOOL_DIR="$TOOLS/$1"
if [ ! -d "$TOOL_DIR" ] ; then echo "Unknown tool: $1"; RET=1; break; fi
## Particular version's dir.
TOOL_HOME="$TOOL_DIR/$2"
if [ ! -d "$TOOL_HOME" ] ; then echo "$1 doesn't have a version: $2"; RET=2; break; fi
mkdir -p ~/sw/tools/.links
mkdir -p ~/sw/tools/.homes
## Commands to perform before running the tool (each time).
if [ -x "$TOOL_DIR/onRun.sh" ] ; then
ON_RUN=$TOOL_DIR/onRun.sh;
fi
## Create the HOME links.
echo "Creating link ~/sw/tools/.homes/$1 -> $TOOL_HOME"
rm ~/sw/tools/.homes/$1
ln -s $TOOL_HOME ~/sw/tools/.homes/$1
## Commands to run upon version switching.
if [ -x "$TOOL_DIR/onSwitch.sh" ] ; then
echo "Running '$TOOL_DIR/onSwitch.sh $TOOL_HOME'...";
$TOOL_DIR/onSwitch.sh $TOOL_HOME;
fi
## Tool's runnable from the path.
## Check the symlink existence.
if [ ! -h $TOOL_DIR/runnable.path ] ; then
#echo "Every tool has to have an (invalid) symlink with the path from tool's HOME to the executable."; RET=3; break;
true;
else
TOOL_RUNNABLE_PATH=$TOOL_HOME/`readlink $TOOL_DIR/runnable.path`
if [ ! -e "$TOOL_RUNNABLE_PATH" ] ; then echo "Non-existent runnable: $TOOL_RUNNABLE_PATH"; RET=4; break; fi
if [ ! -x "$TOOL_RUNNABLE_PATH" ] ; then echo "Non-executable runnable: $TOOL_RUNNABLE_PATH"; RET=5; break; fi
## Create a link to the runnable in ~/sw/tools/.links/, named like the tool name.
createRunnableScript $1 $2 $TOOL_RUNNABLE_PATH $TOOL_HOME $ON_RUN
fi
if [ -x "$TOOL_DIR/runnables.txt" ] ; then
## Link runnables listed in a file /sw/tools/<tool>/runnables.txt .
## TODO: Find automatically all executables from the tool's dir.
## Upon creation of those, remove links pointing to the particular tool's dir.
for RUNNABLE_SUBPATH in `cat $TOOL_DIR/runnables.txt`; do
TOOL_RUNNABLE_PATH=$TOOL_HOME/$RUNNABLE_SUBPATH;
if [ ! -e "$TOOL_RUNNABLE_PATH" ] ; then echo "Non-existent runnable: $TOOL_RUNNABLE_PATH"; RET=4; break 2; fi
if [ ! -x "$TOOL_RUNNABLE_PATH" ] ; then echo "Non-executable runnable: $TOOL_RUNNABLE_PATH"; RET=5; break 2; fi
done
for RUNNABLE_SUBPATH in `cat $TOOL_DIR/runnables.txt`; do
TOOL_RUNNABLE_PATH=$TOOL_HOME/$RUNNABLE_SUBPATH;
createRunnableScript $1 $2 $TOOL_RUNNABLE_PATH $TOOL_HOME $ON_RUN
done
else
## runnables.txt does not exist, scan the dir for executable files and links.
#for RUNNABLE_SUBPATH in `ls -l $TOOL_HOME/bin | grep -e ^[-l]..x | cut -b47- | cut -d' ' -f1`; do
#TOOL_RUNNABLE_PATH=$TOOL_HOME/bin/$RUNNABLE_SUBPATH;
for TOOL_RUNNABLE_PATH in $TOOL_HOME/bin/* ; do if [ -x "$TOOL_RUNNABLE_PATH" -a -f "$TOOL_RUNNABLE_PATH" ] ; then
createRunnableScript $1 $2 $TOOL_RUNNABLE_PATH $TOOL_HOME $ON_RUN
fi ; done
fi
break;
done # while true
## Clear bash's cache.
hash -r
## If called without `source`, return an exit code.
if [ "$0" == "switch.sh" ] ; then exit $RET; fi
