diff --git a/INSTALL.sh b/INSTALL.sh
index 7ff4929..3a6954a 100755
--- a/INSTALL.sh
+++ b/INSTALL.sh
@@ -1,56 +1,133 @@
 #!/bin/bash
 
-echo "Creating directories..."
-mkdir -p ${HOME}/.capt/root
-mkdir -p ${HOME}/.capt/debs_temp
+################################################################################
+#                         Function declarations
+################################################################################
 
-echo "Creating installer script..."
-cat <<"EOF" >${HOME}/.capt/capt
-#!/bin/bash
+function fail () {
+	echo ${@:-"Install encountered and error\nExiting..."} > /dev/stderr
+	exit 1
+}
 
-cd ${HOME}/.capt/debs_temp
-rm -rf *.deb
-if [[ $1 == "install" ]]; then
-	echo "Downloading prerequisites..."
-	apt-get download $(apt-cache depends --recurse --no-recommends --no-suggests --no-conflicts --no-breaks --no-replaces --no-enhances $2 | grep "^\w" | sort -u)
-	echo "Installing..."
-	find . -iname "*.deb" -type f -exec dpkg -x {} ${HOME}/.capt/root \;
-	echo "Finished installing, removing temp files..."
-	rm -rf *.deb
-	echo "Done"
-else
-	echo "Capt only supports \`capt install\`"
-fi
+function bash_install {
+	local bashrc="${HOME}/.bashrc"
 
-EOF
+	echo "Adding stuff to bashrc"
+	if grep "# add capt to PATH" "$bashrc" > /dev/null; then return 0; fi
+	cat <<- EOF >> "$bashrc" || fail
 
-echo "Setting executable bit on \`capt\` executable..."
-chmod +x ${HOME}/.capt/capt
+	# add capt to PATH
 
-echo "Adding stuff to zshrc"
-cat <<EOF >>${HOME}/.zshrc
-export LD_LIBRARY_PATH=${HOME}/.capt/root/lib/x86_64-linux-gnu:${HOME}/.capt/root/usr/lib/x86_64-linux-gnu:$LD_LIBRARY_PATH
-export PATH=${HOME}/.capt:${HOME}/.capt/root/usr/local/sbin:${HOME}/.capt/root/usr/local/bin:${HOME}/.capt/root/usr/sbin:${HOME}/.capt/root/usr/bin:${HOME}/.capt/root/sbin:${HOME}/.capt/root/bin:${HOME}/.capt/root/usr/games:${HOME}/.capt/root/usr/local/games:${HOME}/.capt/snap/bin:$PATH
+	export LD_LIBRARY_PATH=${CAPT_DIR}/root/lib/x86_64-linux-gnu:${CAPT_DIR}/root/usr/lib/x86_64-linux-gnu:\$LD_LIBRARY_PATH
+	export PATH=${CAPT_DIR}:${CAPT_DIR}/root/usr/local/sbin:${CAPT_DIR}/root/usr/local/bin:${CAPT_DIR}/root/usr/sbin:${CAPT_DIR}/root/usr/bin:${CAPT_DIR}/root/sbin:${CAPT_DIR}/root/bin:${CAPT_DIR}/root/usr/games:${CAPT_DIR}/root/usr/local/games:${CAPT_DIR}/snap/bin:\$PATH
+	EOF
+}
 
-EOF
+function zsh_install {
+	local zshrc="${HOME}/.zshrc"
 
-echo "Adding stuff to bashrc"
-cat <<EOF >>${HOME}/.bashrc
-export LD_LIBRARY_PATH=${HOME}/.capt/root/lib/x86_64-linux-gnu:${HOME}/.capt/root/usr/lib/x86_64-linux-gnu:$LD_LIBRARY_PATH
-export PATH=${HOME}/.capt:${HOME}/.capt/root/usr/local/sbin:${HOME}/.capt/root/usr/local/bin:${HOME}/.capt/root/usr/sbin:${HOME}/.capt/root/usr/bin:${HOME}/.capt/root/sbin:${HOME}/.capt/root/bin:${HOME}/.capt/root/usr/games:${HOME}/.capt/root/usr/local/games:${HOME}/.capt/snap/bin:$PATH
+	echo "Adding stuff to zshrc"
+	if grep "# add capt to PATH" "$zshrc" > /dev/null; then return 0; fi
+	cat <<- EOF >> "$zshrc" || fail
 
-EOF
+	# add capt to PATH
+
+	export LD_LIBRARY_PATH=${CAPT_DIR}/root/lib/x86_64-linux-gnu:${CAPT_DIR}/root/usr/lib/x86_64-linux-gnu:\$LD_LIBRARY_PATH
+	export PATH=${CAPT_DIR}:${CAPT_DIR}/root/usr/local/sbin:${CAPT_DIR}/root/usr/local/bin:${CAPT_DIR}/root/usr/sbin:${CAPT_DIR}/root/usr/bin:${CAPT_DIR}/root/sbin:${CAPT_DIR}/root/bin:${CAPT_DIR}/root/usr/games:${CAPT_DIR}/root/usr/local/games:${CAPT_DIR}/snap/bin:\$PATH
+	EOF
+}
 
-FISHRC=${HOME}/.config/fish/config.fish
-if [ -f $FISHRC ]; then
+function fish_install {
+	local DEFAULT_FISHRC="${HOME}/.config/fish/config.fish"
+	local FISHRC=${DEFAULT_FISHRC}
+
+	if [ ! -f "${FISHRC}" ]; then
+		read -p "File 'config.fish' not in expected location.\n Enter path to config.fish. Leave blank to use default location anyway.\n$PS2" FISHRC
+		if [ -z "$FISHRC" ]; then
+			echo "Using default location '${DEFAULT_FISHRC}'"
+			FISHRC="${DEFAULT_FISHRC}"
+			mkdir -p $(dirname "${DEFAULT_FISHRC}") || fail
+		elif ![ -f  $FISHRC ]; then
+			echo "config.fish not in entered location. Aborting..."
+			exit 1
+		fi
+	fi
 	echo "Adding stuff to fishrc"
-	cat <<EOF >>$FISHRC
+	if grep "# add capt to PATH" "$FISHRC" > /dev/null; then return 0; fi
+	cat <<- EOF >> "$FISHRC" || fail "Cannot write to 'config.fish'"
+
+	# add capt to PATH
+
+	set -p LD_LIBRARY_PATH ${CAPT_DIR}/root/lib/x86_64-linux-gnu:${CAPT_DIR}/root/usr/lib/x86_64-linux-gnu
+	set -p PATH ${CAPT_DIR}:${CAPT_DIR}/root/bin:${CAPT_DIR}/root/sbin:${CAPT_DIR}/root/usr/bin:${CAPT_DIR}/root/usr/sbin:${CAPT_DIR}/root/usr/games:${CAPT_DIR}/root/usr/local/bin:${CAPT_DIR}/root/usr/local/sbin:${CAPT_DIR}/root/usr/local/games:${CAPT_DIR}/snap/bin
+	EOF
+}
 
-# add capt to PATH
+################################################################################
+#                                Script start
+################################################################################
 
-set -p LD_LIBRARY_PATH ${HOME}/.capt/root/lib/x86_64-linux-gnu:${HOME}/.capt/root/usr/lib/x86_64-linux-gnu
-set -p PATH ${HOME}/.capt:${HOME}/.capt/root/bin:${HOME}/.capt/root/sbin:${HOME}/.capt/root/usr/bin:${HOME}/.capt/root/usr/sbin:${HOME}/.capt/root/usr/games:${HOME}/.capt/root/usr/local/bin:${HOME}/.capt/root/usr/local/sbin:${HOME}/.capt/root/usr/local/games:${HOME}/.capt/snap/bin
+CAPT_DIR="${HOME}/sgoinfre/.capt"
+echo "Creating directories..."
+mkdir -p ${CAPT_DIR}/root || fail
+mkdir -p ${CAPT_DIR}/debs_temp || fail
+
+echo "Creating installer script..."
+cat << EOF > ${CAPT_DIR}/capt || fail
+#!/bin/bash
+
+CAPT_DIR="${CAPT_DIR}"
 EOF
+cat << "EOF" >> ${CAPT_DIR}/capt || fail
+cd ${CAPT_DIR}/debs_temp
+rm -rf *.deb
+if [[ $# < 2 || "$1" != "install" ]]; then
+	echo "Capt only supports 'apt install [packages...]'"
+	exit 1
 fi
+shift
+echo "Downloading prerequisites..."
+PACKAGES_DOWNLOADED=0
+while [ $# -gt 0 ]; do
+	if apt-cache depends $1 > /dev/null; then
+		apt-get download $(apt-cache depends --recurse --no-recommends --no-suggests --no-conflicts --no-breaks --no-replaces --no-enhances $1 | grep "^\w" | sort -u)
+		((PACKAGES_DOWNLOADED++))
+	fi
+	shift
+done
+if [ $PACKAGES_DOWNLOADED -eq 0 ]; then
+	exit 1
+fi
+echo -n "Installing packages"
+find . -iname "*.deb" -type f -exec echo -n "." \; -exec dpkg -x {} ${CAPT_DIR}/root \;
+echo
+echo "Finished installing, removing temp files..."
+rm -rf *.deb
+echo "Done"
+EOF
+
+echo "Setting executable bit on \`capt\` executable..."
+chmod +x ${CAPT_DIR}/capt || fail
+
+echo "Which shell do you use?(zsh is default at Codam)"
+select selection in "zsh" "bash" "fish"; do
+	selection=${selection:-${REPLY}}
+	case $selection in
+		"zsh")
+			zsh_install
+			break
+			;;
+		"bash")
+			bash_install
+			break
+			;;
+		"fish")
+			fish_install
+			break
+			;;
+		*)
+			echo "Invalid input"
+	esac
+done
 
 echo "Done, please restart your shell or run \`source ${HOME}/.zshrc\` / \`source ${HOME}/.bashrc\` / \'source ${HOME}/.config/fish/config.fish\' (depending on your shell)"
diff --git a/README.md b/README.md
index d8423de..50c2814 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,10 @@
 Replacement for `apt` for use at Codam Linux stations. Might be compatible with other 42 Network Linux systems as well.
 
 How to install `capt`\
-Download & run `installer.sh`: `wget https://raw.githubusercontent.com/PanoramixDeDruide/Codam_apt/main/INSTALL.sh && chmod +x INSTALL.sh && ./INSTALL.sh`
+Download & run `installer.sh`:
+```
+wget https://raw.githubusercontent.com/MFelida/codam-apt/main/INSTALL.sh && chmod +x INSTALL.sh && ./INSTALL.sh
+```
 
 How to check if the `apt` package of your choice is available\
 -Run `apt-cache search <package-name>`