Bash script to automate oracle instant client setup

instant-client.sh

#!/bin/sh

# First check to ensure that an instant client instance isn't already installed
# by determining if a symlink exists within /usr/local/lib.
if [ -e "/usr/local/lib/libclntsh.dylib" ] # If symlink file exists
then
    # If one already exists nothing new has to be done, just exit
    echo "[*] Looks like an Instant Client is already installed on this machine"
    echo "      Instant Client Location: $(readlink '/usr/local/lib/libclntsh.dylib')"
    echo "[*] Exiting..."
    exit 0
fi

# Script vars
INSTANT_CLIENT_DMG_NAME="instantclient-basiclite-macos.x64-19.8.0.0.0dbru.dmg"
INSTANT_CLIENT_VOLUME_NAME="instantclient-basiclite-macos.x64-19.8.0.0.0dbru"
INSTANT_CLIENT_FOLDER="instantclient_19_8"
CLIENT_FINAL_INSTALL_LOCATION="$HOME/Documents/$INSTANT_CLIENT_FOLDER"

cd $HOME/Downloads

# Download Instant Client 19.8 dmg if it doesn't already exist
if [ -e "$INSTANT_CLIENT_DMG_NAME" ]
then
    # Downloaded DMG already exists
    echo "[*] DMG file already exists in $HOME/Downloads. Skipping download step"
else
    echo "[*] Downloading $INSTANT_CLIENT_DMG_NAME"
    curl -O https://download.oracle.com/otn_software/mac/instantclient/198000/"$INSTANT_CLIENT_DMG_NAME"
fi

# Check whether unpacked DMG directory already exists
if [ -d "$INSTANT_CLIENT_FOLDER" ]
then
    echo "[*] Unpacked instant client files already exist in Downloads. Skipping DMG mount step"
else
    # Mount the downloaded DMG file and run its install script, then unmount
    echo "[*] Mounting and installing DMG image files..."
    hdiutil mount "$INSTANT_CLIENT_DMG_NAME" > /dev/null
    /Volumes/"$INSTANT_CLIENT_VOLUME_NAME"/install_ic.sh
    hdiutil unmount /Volumes/"$INSTANT_CLIENT_VOLUME_NAME" > /dev/null
    echo "[*] Files installed and DMG unmounted"
fi

# By default the install script moves files into $USER/Downloads/instantclient_19_8
# Some apps are not allowed to access the Downloads folder, so move it into a directory
# specified by this script's command line argument (or $USER/Documents by default)
if [ $# -eq 0 ]
then
    # If no args supplied use Documents as default directory to move files into
    echo "[*] Moving files into directory ($HOME/Documents/$INSTANT_CLIENT_FOLDER)"
    mkdir "$HOME/Documents/$INSTANT_CLIENT_FOLDER"
    mv "$INSTANT_CLIENT_FOLDER" "$HOME/Documents/"
else
    # Move files into specified directory
    CLIENT_FINAL_INSTALL_LOCATION="$1/$INSTANT_CLIENT_FOLDER"

    echo "[*] Moving files into directory ($1/$INSTANT_CLIENT_FOLDER)"
    mkdir -p "$1" # -p flag creates non-existing parent dirs
    mv "$INSTANT_CLIENT_FOLDER" "$1/"
fi

# Ensure last mv command ran successfully (returned 0)
if [ $? -eq 0 ]
then
   # Create symlink for the client's directory to /usr/local/lib
    echo "[*] Files moved. Creating symlink between $CLIENT_FINAL_INSTALL_LOCATION/libclntsh.dylib and /usr/local/lib"
    mkdir /usr/local/lib > /dev/null 2>&1 # Hide stderr output since dir might already exist
    ln -s "$CLIENT_FINAL_INSTALL_LOCATION/libclntsh.dylib" /usr/local/lib

    if [ $? -eq 0 ]
    then
        echo "[*] Instant Client has been setup for this machine"
    fi
fi