Simple bash functions to manage different Scala versions on the command line

scala-env.sh

#!/bin/bash -e

# where Scala tarballs are extracted
SCALA_BASE=$HOME/scala

# Usage:
#
# Install:
# . /path/to/scala-env.sh in your bash profile
#
# Switch scala version:
# set-scala 2.12.11
#
# Download Scala version:
# download-scala 2.13.2
#

# Set current Scala version for the command line.
#
# $1 scala version, like "2.12.1"
function set-scala()
{
    local ver=$1
    local dir="$SCALA_BASE/scala-$1"
    if [ -d $dir ]; then
        # attempt to not duplicate scala installations on the PATH
        local regex="s|$HOME/scala/scala-2\.[0-9][0-9]\.[0-9][0-9]?/bin/?:||"
        stripped=$(echo $PATH | sed -E $regex)
        export PATH=$dir/bin/:$stripped
    else
        echo "Unknown Scala version. Download it with 'download-scala $ver'"
    fi
}

# $1 scala version, like "2.12.1"
function download-scala()
{
    local ver=$1
    local dir="$SCALA_BASE/scala-$1"
    if [ -d $dir ]; then
        echo "$dir already exists. If installation is broken, delete and retry."
    else
        (cd $HOME/Downloads/ && curl https://downloads.lightbend.com/scala/$ver/scala-$ver.tgz -O)
        tar -C$SCALA_BASE -xzf $HOME/Downloads/scala-$ver.tgz
    fi
}