Creates uramdisk.tar.gz from ramdisk.tar.gz - AND/OR - Installs Linux Kernel modules on ramdisk

uramdisk_create_install_kernel_modules.sh

#!/usr/bin/env bash 
#
# Installs Kernel modules on ramdisk and/or creates uramdisk from ramdisk.
#
# Tested on Ubuntu.

# Invoking with arguments:
#   -m                  > install kernel modules on ramdisk
#   -u                  > create uramdisk from ramdisk
#   -mu / no arguments  > do both

# -----------------------------------------------------------------------------
# Configuration
CROSS_COMPILE=/opt/Xilinx/SDK/2014.1/gnu/arm/lin/bin/arm-xilinx-linux-gnueabi-
KERNEL_SRC_PATH=~/linux-xlnx-xilinx-v2013.4-trd
IMG_IN=ramdisk.image.gz
ARCH=arm

# -----------------------------------------------------------------------------
# Execution
MNT_DIR=$(mktemp -d /tmp/ramdisk-tmp.XXXXXXXXXX)

# Process command line arguments
ISM=
ISU=

if [ "$#" -eq 0 ]; then
    ISM=y
    ISU=y
else
    while getopts ":mu" opt; do
        case $opt in
            m) ISM=y ;;
            u) ISU=y ;;
            \?) echo "Invalid option: -$OPTARG" >&2 ;;
        esac
    done
fi

# -m
if [ -n "$ISM" ]; then
    echo "Installing modules..."
    echo -e "\e[1m[root permisions required]\e[0m Mounting ramdisk image"
    sudo true

    cp "$IMG_IN" "${IMG_IN}_bak"                        # backup
    gunzip "$IMG_IN"
    [ ! -e "$MNT_DIR" ] && mkdir -p "$MNT_DIR"          # create if doesn't exist
    sudo mount -o loop "${IMG_IN%%.gz}" "$MNT_DIR"      # mount image

    # >> ENTER Kernel directory >>
    pushd "${KERNEL_SRC_PATH}"

    # install kernel modules on ramdisk image
    sudo rm -r "${MNT_DIR}/lib/modules/"
    sudo make modules ARCH="${ARCH}" INSTALL_MOD_PATH="${MNT_DIR}" CROSS_COMPILE="${CROSS_COMPILE}"
    sudo make modules_install ARCH="${ARCH}" INSTALL_MOD_PATH="${MNT_DIR}" CROSS_COMPILE="${CROSS_COMPILE}"  

    # << EXIT Kernel directory  <<
    popd

    # remove superfluous links
    sudo rm -v "${MNT_DIR}"/lib/modules/*/build
    sudo rm -v "${MNT_DIR}"/lib/modules/*/source

    # unmount and compress image
    sudo umount "$MNT_DIR"
    [ -e "$MNT_DIR" ] && sudo rm -rf "$MNT_DIR"
    gzip -9 "${IMG_IN%%.gz}"
fi

# -u
if [ -n "$ISU" ]; then
    echo "creating uramdisk..."
    mkimage -A "${ARCH}" -T ramdisk -C gzip -d "$IMG_IN" "u${IMG_IN}"
fi