this script is based on another for Sublime Text (http://www.simonewebdesign.it/install-sublime-text-3-on-linux/). It will handle updates (detects the latest developer or nightly edition) and locale (using your $LANG environment variable) (only tested on a 64 bit, fedora system, feedback welcome).

update_firefox_developer_edition.sh

#!/bin/sh

# Firefox Developer Edition install
# No need to download this script, just run it on your terminal:
#  $  curl -L git.io/firefoxdev | sh
# When you need to update Firefox Developer Edition, run this script again.

START_CMD="firefox-dev"
INSTALLATION_DIR="/opt/${START_CMD}"

# Detect the locale
LOCALE=$(echo ${LANG/_/-} | cut -d. -f1)
 
# Download the tarball, unpack and install
URL="https://download.mozilla.org/?product=firefox-devedition-latest-ssl&os=linux64&lang=${LOCALE}"
curl -L -o ${HOME}/${START_CMD}.tar.bz2 $URL
if tar -xf ${HOME}/${START_CMD}.tar.bz2 --directory=${HOME}; then
  # Create an application launcher file based on the regular firefox launcher
  cat /usr/share/applications/firefox.desktop | sed -r 's/Name=Firefox/Name=Firefox Developer Edition/g' | sed -r "s/Exec=firefox %u/Exec=${START_CMD} %u/g" | sed -r "s/Icon=firefox/Icon=$(echo ${INSTALLATION_DIR} | sed -r 's/\//\\\//g')\/browser\/chrome\/icons\/default\/default128.png/g" > ${HOME}/firefox/firefox.desktop
  # Remove the installation folder and the symlink, they might already exist
  sudo rm -rf ${INSTALLATION_DIR} /bin/${START_CMD}
  sudo mv ${HOME}/firefox ${INSTALLATION_DIR}
  sudo ln -s ${INSTALLATION_DIR}/firefox /bin/${START_CMD}
fi
rm ${HOME}/${START_CMD}.tar.bz2
 
# Add to applications list
sudo ln -sf ${INSTALLATION_DIR}/firefox.desktop /usr/share/applications/${START_CMD}.desktop
 
echo ""
echo "Firefox Developer Edition installed."
echo "Run with: ${START_CMD}"

update_firefox_nightly_edition.sh

#!/bin/sh

# Firefox Nightly Edition install
# No need to download this script, just run it on your terminal:
#  $  curl -L git.io/firefoxnightly | sh
# When you need to update Firefox Nightly Edition, run this script again.

START_CMD="firefox-nightly"
INSTALLATION_DIR="/opt/${START_CMD}"

# Detect the locale
LOCALE=$(echo ${LANG/_/-} | cut -d. -f1)

# Download the tarball, unpack and install
URL="https://download.mozilla.org/?product=firefox-nightly-latest-ssl&os=linux64&lang=${LOCALE}"
curl -L -o ${HOME}/${START_CMD}.tar.bz2 $URL
if tar -xf ${HOME}/${START_CMD}.tar.bz2 --directory=${HOME}; then
  # Create an application launcher file based on the regular firefox launcher
  cat /usr/share/applications/firefox.desktop | sed -r 's/Name=Firefox/Name=Firefox Nightly Edition/g' | sed -r "s/Exec=firefox %u/Exec=${START_CMD} %u/g" | sed -r "s/Icon=firefox/Icon=$(echo ${INSTALLATION_DIR} | sed -r 's/\//\\\//g')\/browser\/chrome\/icons\/default\/default128.png/g" > ${HOME}/firefox/firefox.desktop
  # Remove the installation folder and the symlink, they might already exist
  sudo rm -rf ${INSTALLATION_DIR} /bin/${START_CMD}
  sudo mv ${HOME}/firefox ${INSTALLATION_DIR}
  sudo ln -s ${INSTALLATION_DIR}/firefox /bin/${START_CMD}
fi
rm ${HOME}/${START_CMD}.tar.bz2
 
# Add to applications list
sudo ln -sf ${INSTALLATION_DIR}/firefox.desktop /usr/share/applications/${START_CMD}.desktop
 
echo ""
echo "Firefox Nightly Edition installed."
echo "Run with: ${START_CMD}"

update_golang.sh

#!/bin/sh

# golang install (last update: Thursday 31 May 2018)
# No need to download this script, just run it on your terminal:
#     curl -L https://gist.github.com/grenade/3b3c5b17586881d01142/raw/update_golang.sh | sh

OS="linux"
INSTALL_DIR_PARENT="/usr/local"
if [[ "$(uname -m)" = "x86_64" ]]; then
  ARCHITECTURE="amd64"
else
  ARCHITECTURE="386"
fi

# todo: obtain latest checksum and validate download
VERSION="$(echo $(curl -s https://golang.org/dl/) | sed -rn "s#.*<a class=\"download downloadBox\" href=\"https:\/\/dl\.google\.com\/go\/go([0-9\.]+)\.${OS}-${ARCHITECTURE}\.tar\.gz\">.*#\1#p")"

ARCHIVE="go${VERSION}.${OS}-${ARCHITECTURE}.tar.gz"
INSTALL_DIR="${INSTALL_DIR_PARENT}/go${VERSION}.${OS}-${ARCHITECTURE}"

rm -f ${HOME}/Downloads/${ARCHIVE}
curl -o ${HOME}/Downloads/${ARCHIVE} https://dl.google.com/go/${ARCHIVE}

sudo rm -rf ${INSTALL_DIR}
sudo mkdir -p ${INSTALL_DIR}
if sudo tar -C ${INSTALL_DIR} -xzf ${HOME}/Downloads/${ARCHIVE}; then
  sudo rm -rf /usr/local/go
  sudo ln -sf ${INSTALL_DIR}/go /usr/local/go
  rm -f ${HOME}/Downloads/${ARCHIVE}
fi

echo ""
echo "go ${VERSION} installed."

update_skype.sh

#!/bin/sh

# Skype install
# No need to download this script, just run it on your terminal:
#  $  curl -L https://gist.githubusercontent.com/grenade/3b3c5b17586881d01142/raw/update_skype.sh | sh
# When you need to update Skype, run this script again.

START_CMD="skype"
INSTALLATION_DIR="/opt/skype"

URL="http://www.skype.com/go/getskype-linux-beta-dynamic"
 
# Download the tarball, unpack and install
curl -L -o $HOME/$START_CMD.tar.bz2 $URL
if tar -xf $HOME/$START_CMD.tar.bz2 --directory=$HOME; then
  # Remove the installation folder and the symlink, they might already exist
  sudo rm -rf $INSTALLATION_DIR /bin/$START_CMD
  sudo mv $HOME/skype-* $INSTALLATION_DIR
  sudo ln -s $INSTALLATION_DIR/skype /bin/$START_CMD
fi
rm $HOME/$START_CMD.tar.bz2
 
# Add to applications list
for i in 16 32 48 64 128; do sudo cp $INSTALLATION_DIR/icons/SkypeBlue_${i}x${i}.png /usr/share/icons/hicolor/${i}x$i/apps/$START_CMD.png; done
sudo ln -s $INSTALLATION_DIR/skype.desktop /usr/share/applications/$START_CMD.desktop

# Install dependencies
sudo dnf install -y libX11.i686 libv4l.i686 alsa-plugins-pulseaudio.i686 qt-x11.i686 libXScrnSaver.i686 libXv-1.0.10-2.fc22.i686 qtwebkit-2.3.4-6.fc22.i686
 
echo ""
echo "Skype installed successfully!"
echo "Run with: $START_CMD"

update_sublime_text_3.sh

#!/bin/sh

# Sublime Text 3 Install (last update: Monday 8 April 2019)
# No need to download this script, just run it on your terminal:
#     curl -sL https://gist.github.com/grenade/3b3c5b17586881d01142/raw/update_sublime_text_3.sh | sh

# Detect the architecture
if [[ "$(uname -m)" = "x86_64" ]]; then
  ARCHITECTURE="x64"
else
  ARCHITECTURE="x32"
fi

# Fetch the latest build version number (thanks daveol)
BUILD=$(echo $(curl -s http://www.sublimetext.com/3) | sed -rn "s#.*<p class=\"latest\"><i>Version:<\/i> Build ([0-9]+)..*#\1#p")
echo "detected available release: ${BUILD}"

URL="https://download.sublimetext.com/sublime_text_3_build_${BUILD}_${ARCHITECTURE}.tar.bz2"

if [ -L /usr/local/bin/subl ] && [ -e /usr/local/bin/subl ]; then
  EXISTING_INSTALLATION_DIR=$(dirname $(readlink /usr/local/bin/subl))
  echo "detected previous install at: ${EXISTING_INSTALLATION_DIR}"
  INSTALLATION_DIR=$(dirname ${EXISTING_INSTALLATION_DIR})/sublime_text_${BUILD}
else
  INSTALLATION_DIR="/opt/sublime_text_${BUILD}"
fi
echo "install dir set to: ${INSTALLATION_DIR}"

# Download the tarball, unpack and install
if curl -o ${HOME}/st3.tar.bz2 ${URL}; then
  echo
  echo "downloaded: ${HOME}/st3.tar.bz2 from: ${URL}"
  rm -rf ${HOME}/sublime_text_3
  if tar -xf ${HOME}/st3.tar.bz2 --directory=${HOME}; then
    if [ -d "${INSTALLATION_DIR}" ] && sudo rm -rf ${INSTALLATION_DIR}; then
      echo "deleted: ${INSTALLATION_DIR}"
    fi
    sudo mv ${HOME}/sublime_text_3 ${INSTALLATION_DIR}
    sudo rm -f /opt/sublime_text
    sudo ln -sf ${INSTALLATION_DIR} /opt/sublime_text
    sudo ln -sf ${INSTALLATION_DIR}/sublime_text /usr/local/bin/subl

    # Add to applications list
    if sed -i -e 's/Icon=sublime-text/Icon=\/opt\/sublime_text\/Icon\/256x256\/sublime-text.png/g' ${INSTALLATION_DIR}/sublime_text.desktop; then
      echo "icon path set in: ${INSTALLATION_DIR}/sublime_text.desktop"
    fi
    if sudo ln -sf ${INSTALLATION_DIR}/sublime_text.desktop /usr/share/applications/sublime_text.desktop; then
      echo "symlink: /usr/share/applications/sublime_text.desktop created with target: ${INSTALLATION_DIR}/sublime_text.desktop"
    fi
    echo
    echo "sublime text 3 installation complete."
    echo "run with: subl"
  else
    echo "failed to extract: ${HOME}/st3.tar.bz2 to: ${HOME}"
  fi
  if rm ${HOME}/st3.tar.bz2; then
    echo "deleted: ${HOME}/st3.tar.bz2"
  else
    echo "failed to delete: ${HOME}/st3.tar.bz2"
  fi
else
  echo "failed to download: ${HOME}/st3.tar.bz2 from: ${URL}"
fi

i wasn't. thank you for pointing that out @RichieMcG. corrected now.