diff --git a/scripts/_common.sh b/scripts/_common.sh
index e4228e7..cfc17c4 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -1,3 +1,5 @@
 #!/bin/bash
 
 VERSION="1.1.6"
+
+JAPPIX_SOURCE_URL="https://github.com/jappix/jappix/archive/${VERSION}.tar.gz"
diff --git a/scripts/backup b/scripts/backup
index cfc71a3..4b7a6c6 100644
--- a/scripts/backup
+++ b/scripts/backup
@@ -1,5 +1,4 @@
 #!/bin/bash
-app=jappix
 
 # causes the shell to exit if any subcommand or pipeline returns a non-zero status
 set -e
@@ -7,7 +6,7 @@ set -e
 # Source YNH helpers
 . /usr/share/yunohost/helpers
 
-app=${!#}
+app="jappix"
 
 # Retrieve app settings
 domain=$(sudo yunohost app setting "$app" domain)
diff --git a/scripts/install b/scripts/install
index f4a41be..953fb34 100644
--- a/scripts/install
+++ b/scripts/install
@@ -1,61 +1,55 @@
 #!/bin/bash
 
+set -e
+
 source ./_common.sh
 
+app="jappix"
+
 # Retrieve arguments
 domain=$1
-path=$2
+path=${2%/}
 name=$3
 language=$4
 
 # Check domain/path availability
-sudo yunohost app checkurl $domain$path -a jappix
-if [[ ! $? -eq 0 ]]; then
-exit 1
-fi
-
-# Remove trailing "/" for next commands
-path=${path%/}
+sudo yunohost app checkurl "${domain}${path}" -a "$app" \
+  || exit 1
 
 # Retrieve sources
-wget -nv -q -O jappix.tar.gz https://github.com/jappix/jappix/archive/${VERSION}.tar.gz
+wget -q -O jappix.tar.gz "$JAPPIX_SOURCE_URL"
 
 # Copy files to the right place
-final_path=/var/www/jappix
-sudo mkdir -p $final_path
-sudo tar -C $final_path -xf jappix.tar.gz --strip-components 1
-sudo mkdir -p $final_path/store/conf
-sudo cp ../conf/*.xml $final_path/store/conf/
+final_path="/var/www/${app}"
+sudo mkdir -p "${final_path}/store/conf"
+sudo tar -C "$final_path" -xf jappix.tar.gz --strip-components 1
+sudo cp ../conf/*.xml "${final_path}/store/conf/"
 
 # Set permissions to jappix directory
-sudo chown -R www-data: $final_path
+sudo chown -R www-data: "$final_path"
 
-# Modify Nginx configuration file and copy it to Nginx conf directory
-sudo sed -i "s@PATHTOCHANGE2@$path@g" ../conf/nginx.conf
+# Set and copy NGINX configuraion
+sudo sed -i "s@PATHTOCHANGE2@${path}@g" ../conf/nginx.conf
+path=${path:-/}
+sudo sed -i "s@PATHTOCHANGE@${path}@g" ../conf/nginx.conf
+sudo sed -i "s@ALIASTOCHANGE@${final_path}/@g" ../conf/nginx.conf
+sudo cp ../conf/nginx.conf "/etc/nginx/conf.d/${domain}.d/${app}.conf"
 
-if [ -z "$path" ]; then
-  path="/"
-fi
+# Validate language
+[[ -a "${final_path}/i18n/${language}" ]] \
+  || language="en"
 
-sudo ls $final_path/i18n/$language > /dev/null 2>&1
-if [ $? != 0 ];
-then
-  language="en"
-fi
+# Store app settings
+sudo yunohost app setting "$app" name -v "$name"
+sudo yunohost app setting "$app" language -v "$language"
 
-sudo yunohost app setting jappix name -v $name
-sudo yunohost app setting jappix language -v $language
+# Set Jappix configuration
+sudo sed -i "s@PATHTOCHANGE@${path}@g" "${final_path}/store/conf/main.xml"
+sudo sed -i "s@PATHTOCHANGE@${path}@g" "${final_path}/store/conf/hosts.xml"
+sudo sed -i "s@DOMAINTOCHANGE@${domain}@g" "${final_path}/store/conf/main.xml"
+sudo sed -i "s@CHANGELANG@${language}@g" "${final_path}/store/conf/main.xml"
+sudo sed -i "s@CHANGENAME@${name}@g" "${final_path}/store/conf/main.xml"
+sudo sed -i "s@DOMAINTOCHANGE@${domain}@g" "${final_path}/store/conf/hosts.xml"
 
-sudo sed -i "s@PATHTOCHANGE@$path@g" ../conf/nginx.conf
-sudo sed -i "s@ALIASTOCHANGE@$final_path/@g" ../conf/nginx.conf
-sudo cp ../conf/nginx.conf /etc/nginx/conf.d/$domain.d/jappix.conf
-sudo sed -i "s@PATHTOCHANGE@$path@g" $final_path/store/conf/main.xml
-sudo sed -i "s@PATHTOCHANGE@$path@g" $final_path/store/conf/hosts.xml
-sudo sed -i "s@DOMAINTOCHANGE@$domain@g" $final_path/store/conf/main.xml
-sudo sed -i "s@CHANGELANG@$language@g" $final_path/store/conf/main.xml
-sudo sed -i "s@CHANGENAME@$name@g" $final_path/store/conf/main.xml
-sudo sed -i "s@DOMAINTOCHANGE@$domain@g" $final_path/store/conf/hosts.xml
-
-# Reload Nginx and regenerate SSOwat conf
+# Reload services
 sudo service nginx reload
-sudo yunohost app ssowatconf
diff --git a/scripts/remove b/scripts/remove
index e4d284f..893a4b0 100644
--- a/scripts/remove
+++ b/scripts/remove
@@ -1,8 +1,13 @@
 #!/bin/bash
-domain=$(sudo yunohost app setting jappix domain)
 
-sudo rm -rf /var/www/jappix
-sudo rm -f /etc/nginx/conf.d/$domain.d/jappix.conf
+app="jappix"
 
+# Retrieve arguments
+domain=$(sudo yunohost app setting "$app" domain)
+
+# Remove sources and configuration
+sudo rm -rf "/var/www/${app}"
+sudo rm -f "/etc/nginx/conf.d/${domain}.d/${app}.conf"
+
+# Reload services
 sudo service nginx reload
-sudo yunohost app ssowatconf
diff --git a/scripts/restore b/scripts/restore
index f485e86..66fa81c 100644
--- a/scripts/restore
+++ b/scripts/restore
@@ -1,22 +1,18 @@
 #!/bin/bash
-app=jappix
 
 # causes the shell to exit if any subcommand or pipeline returns a non-zero status
 set -e
 
-app=${!#}
-
-# Retrieve arguments
-backup_dir=$1
+app="jappix"
 
 # Retrieve old app settings
 domain=$(sudo yunohost app setting "$app" domain)
 
 # Restore sources & data
-sudo cp -a "./sources" "/var/www/$app"
+sudo cp -a ./sources "/var/www/${app}"
 
-domain=$(sudo yunohost app setting $app domain)
-sudo cp -a $"./nginx.conf" "/etc/nginx/conf.d/$domain.d/$app.conf"
+# Restore Nginx and YunoHost parameters
+sudo cp -a ./nginx.conf "/etc/nginx/conf.d/${domain}.d/${app}.conf"
 
-# Restart webserver
+# Reload services
 sudo service nginx reload
diff --git a/scripts/upgrade b/scripts/upgrade
index 5c4edaa..245ffe8 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -1,55 +1,50 @@
 #!/bin/bash
 
+set -e
+
 source ./_common.sh
 
-# Retrieve arguments
-domain=$(sudo yunohost app setting jappix domain)
-path=$(sudo yunohost app setting jappix path)
-name=$(sudo yunohost app setting jappix name)
-language=$(sudo yunohost app setting jappix language)
+app="jappix"
 
-if [[ "$name" = "" ]];
-then
-    name="YunoJappix"
-fi
-if [[ "$language" = "" ]];
-then
-    language="en"
-fi
+# Retrieve arguments
+domain=$(sudo yunohost app setting "$app" domain)
+path=$(sudo yunohost app setting "$app" path)
+name=$(sudo yunohost app setting "$app" name)
+language=$(sudo yunohost app setting "$app" language)
+
+# Set default values
+name="${name:-YunoJappix}"
+language="${language:-en}"
 
 # Remove trailing "/" for next commands
 path=${path%/}
 
 # Retrieve sources
-wget -nv -q -O jappix.tar.gz https://github.com/jappix/jappix/archive/${VERSION}.tar.gz
+wget -q -O jappix.tar.gz "$JAPPIX_SOURCE_URL"
 
 # Copy files to the right place
-final_path=/var/www/jappix
-sudo mkdir -p $final_path
-sudo tar -C $final_path -xf jappix.tar.gz --strip-components 1
-sudo mkdir -p $final_path/store/conf
-sudo cp ../conf/*.xml $final_path/store/conf/
+final_path="/var/www/${app}"
+sudo mkdir -p "${final_path}/store/conf"
+sudo tar -C "$final_path" -xf jappix.tar.gz --strip-components 1
+sudo cp ../conf/*.xml "${final_path}/store/conf/"
 
 # Set permissions to jappix directory
-sudo chown -R www-data: $final_path
+sudo chown -R www-data: "$final_path"
 
-# Modify Nginx configuration file and copy it to Nginx conf directory
-sudo sed -i "s@PATHTOCHANGE2@$path@g" ../conf/nginx.conf
+# Set and copy NGINX configuraion
+sudo sed -i "s@PATHTOCHANGE2@${path}@g" ../conf/nginx.conf
+path=${path:-/}
+sudo sed -i "s@PATHTOCHANGE@${path}@g" ../conf/nginx.conf
+sudo sed -i "s@ALIASTOCHANGE@${final_path}/@g" ../conf/nginx.conf
+sudo cp ../conf/nginx.conf "/etc/nginx/conf.d/${domain}.d/${app}.conf"
 
-if [ -z "$path" ]; then
-  path="/"
-fi
+# Set Jappix configuration
+sudo sed -i "s@PATHTOCHANGE@${path}@g" "${final_path}/store/conf/main.xml"
+sudo sed -i "s@PATHTOCHANGE@${path}@g" "${final_path}/store/conf/hosts.xml"
+sudo sed -i "s@DOMAINTOCHANGE@${domain}@g" "${final_path}/store/conf/main.xml"
+sudo sed -i "s@CHANGELANG@${language}@g" "${final_path}/store/conf/main.xml"
+sudo sed -i "s@CHANGENAME@${name}@g" "${final_path}/store/conf/main.xml"
+sudo sed -i "s@DOMAINTOCHANGE@${domain}@g" "${final_path}/store/conf/hosts.xml"
 
-sudo sed -i "s@PATHTOCHANGE@$path@g" ../conf/nginx.conf
-sudo sed -i "s@ALIASTOCHANGE@$final_path/@g" ../conf/nginx.conf
-sudo cp ../conf/nginx.conf /etc/nginx/conf.d/$domain.d/jappix.conf
-sudo sed -i "s@PATHTOCHANGE@$path@g" $final_path/store/conf/main.xml
-sudo sed -i "s@PATHTOCHANGE@$path@g" $final_path/store/conf/hosts.xml
-sudo sed -i "s@DOMAINTOCHANGE@$domain@g" $final_path/store/conf/main.xml
-sudo sed -i "s@CHANGELANG@$language@g" $final_path/store/conf/main.xml
-sudo sed -i "s@CHANGENAME@$name@g" $final_path/store/conf/main.xml
-sudo sed -i "s@DOMAINTOCHANGE@$domain@g" $final_path/store/conf/hosts.xml
-
-# Reload Nginx and regenerate SSOwat conf
+# Reload services
 sudo service nginx reload
-sudo yunohost app ssowatconf