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

Hey, found your install script on the Ask Fedora site. Thanks, it's really neat. Couple of things I found in the Firefox developer edition script:

• \/browser\/icons\/mozicon128.png is way higher res if you've got a desktop that supports it.
• The language detection doesn't work for me in en-AU (Australian English) so I had to hard-code that value in my own script. It's probably fixable, but I reckon a comment in the source would be just as good.

Ok so it somehow works, but it makes firefox directory in home folder, strange hmmm, so I make it hidden folder and create alias for it . My last question: would FF notify me about updates or rather create cron job for it?

Why not populate the ~/.local/share/icons directory with the various icons/sizes and set Icon=ffd.png or something like that?

Doesn't work at my F24 installation:

$ curl -L http://git.io/firefoxdev | sh
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100  1866  100  1866    0     0   1590      0  0:00:01  0:00:01 --:--:--  1590
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 24719    0 24719    0     0  78104      0 --:--:-- --:--:-- --:--:-- 77977
curl: (3) [globbing] unmatched brace in column 99
curl: (6) Could not resolve host: html>
curl: (6) Could not resolve host: <html>
curl: (6) Could not resolve host: <head>
curl: (6) Could not resolve host: <meta
curl: (6) Could not resolve host: charset="UTF-8">
curl: (6) Could not resolve host: <title>Directory
curl: (6) Could not resolve host: Listing
curl: (3) <url> malformed
curl: (6) Could not resolve host: <
curl: (6) Could not resolve host: <body>
curl: (6) Could not resolve host: <h1>Index
curl: (6) Could not resolve host: of
…

thanks for the comments all! i finally got round to updating and tidying up both the dev and nightly scripts today. both should work more reliably again as they now use the officially supported url mechanisms for obtaining latest installers. eg:

• Developer Edition: https://download.mozilla.org/?product=firefox-beta-latest&os=linux64&lang=en-GB
• Nightly Edition: https://download.mozilla.org/?product=firefox-nightly-latest&os=linux64&lang=en-GB

Are you aware that the link points to Firefox Beta and not the Developer Edition?

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