install-python

#!/bin/bash

# set -x

function error_exit {
    echo 
    echo "Error on line $@"
    exit 1
}
trap 'error_exit ${LINENO}' ERR

usage () {
    echo "install-python <version> /install/directory/prefix"
    echo "Likely versions listed at http://python.org/download/releases/"
    exit 1
}
version=$1 ; shift
if [ -z "$1" ] ; then
    usage
fi
prefix="$(readlink -m $1)"
if [ ! -f "$prefix" ] ; then
    mkdir -p $prefix
fi

# derived
srcdir="Python-$version"
tarball="$srcdir.tgz"
url="http://python.org/ftp/python/$version/$tarball"
# a better way to get just the first two digits?
version_2digit="$(echo $version | tr '.' ' ' | awk '{print $1"."$2}')"
executable="$prefix/bin/python${version_2digit}"

download () {
    if [ -f "$tarball" ] ; then
	echo " - file already exists: $tarball"
	return
    fi
    if [ -n "$(which wget)" ] ; then
	echo " + wget'ing $url"
	wget --no-check-certificate -q $url
	return
    fi
    if [ -n "$(which curl)" ] ; then
	echo " + curl'ing $url"
	curl -s $url
	return
    fi
    echo "** Error: no download method **"
    exit 1
}

unpack () {
    if [ -d "$srcdir" ] ; then
	echo " - directory already exists: $srcdir"
	return
    fi
    echo " + unpacking $tarball"
    tar -xzf $tarball
}

install () {
    pushd $srcdir > /dev/null 2>&1

    if [ -f "config.status" ] ; then
	echo " - source already configured: $(pwd)"
    else
	local log="log.configure"
	echo " + configuring, log to $srcdir/$log"
	./configure --prefix=$prefix --disable-shared > $log 2>&1
    fi

    if [ -f "python" ] ; then
	echo " - already built: $(pwd)"
    else
	local log="log.make"
	echo " + building, log to $srcdir/$log"
	make > $log 2>&1
    fi

    if [ -f "$executable" ] ; then
	echo " - already installed: $executable"
    else
	local log="log.install"
	echo " + installing, log to $srcdir/$log"
	make prefix=$prefix install > $log 2>&1
    fi

    if [ ! -x "$executable" ] ; then
	echo "Nothing at $executable"
	echo "Something's broken."
	exit 1
    fi

    popd > /dev/null 2>&1
}

blurb () {
    echo
    echo "Python installed into $prefix"
    echo "You may remove the temporary files:"
    echo 
    echo "  \$ rm -rf $tarball $srcdir"
    echo
    echo "To use this Python set these variables:"
    echo
    echo "  PATH=$prefix/bin:\$PATH"
    echo
}

download
unpack
install
blurb