Ytdyklly

Review for optimization, code standards, missed validation and dependency checks.

Review version 3. What's new:

• apply previous code review


• input arguments and validation


• MySQL management (optional)


• install option (.desktop file), what allows some input values be predefined


• attempt to install dependency when no choice to get user input (GUI version without zenity)

I'm a web programmer, don't known things to make system GUI. So, that's why use bash with zenity. It was interesting to learn bash features. Answers are good, new version to come. Web is unsuitable for task more as bash.

GitHub

#!/bin/bash



webmaster="$(id -un)"   # user who access web files. group is www-data

webgroup="www-data"     # apache2 web group, does't need to be webmaster group. SGID set for folder.

maindomain=".localhost" # domain for creating subdomains, leading dot required

virtualhost="*"         # ip of virtualhost in case server listen on many interfaces or "*" for all

virtualport="80"        # port of virtualhost. apache2 must listen on that ip:port

serveradmin="webmaster@localhost" # admin email

# declare -a webroots=("/home/${webmaster}/Web/${host}"

#                      "/var/www/${host}"

#                      "/var/www/${webmaster}/${host}")

# declared below, after a chanse to edit inlined variadles

webroot=0              # folder index in webroots array

a2ensite="050-"        # short prefix for virtualhost config file

apachehost="/etc/apache2/sites-available/${a2ensite}"   # prefix for virtualhost config file

tmphost=$(mktemp)      # temp file for edit config

trap 'rm "$tmphost"' EXIT # rm temp file on exit

host=""                # no default subdomain

skipmysql=""

mysqladmin="root"

mysqladminpwd=""





have_command() {

  type -p "$1" >/dev/null

}



in_terminal() {

  [ -t 0 ]

}

in_terminal && start_in_terminal=1



info_user() {

  local msg=$1

  local windowicon="info" # 'error', 'info', 'question' or 'warning' or path to icon

  [ "$2" ] && windowicon="$2"

  if in_terminal; then

    echo "$msg"

  else

    zenity --info --text="$msg" --icon-name="${windowicon}" 

           --no-wrap --title="Virtualhost" 2>/dev/null

  fi

}



notify_user () {

  echo "$1" >&2

  in_terminal && return

  local windowicon="info" # 'error', 'info', 'question' or 'warning' or path to icon

  local msgprefix=""

  local prefix="Virtualhost: "

  [ "$2" ] && windowicon="$2" && msgprefix="$2: "

  if have_command zenity; then

    zenity --notification --text="${prefix}$1" --window-icon="$windowicon"

    return

  fi

  if have_command notify-send; then

    notify-send "${prefix}${msgprefix}$1"

  else

    xmessage -buttons Ok:0 -nearmouse "${prefix}${msgprefix}$1" -timeout 10

  fi

}



# sudo apt hangs when run from script, thats why terminal needed

install_zenity() {

  have_command gnome-terminal && gnome-terminal --title="$1" --wait -- $1

  have_command zenity && exit 0

  exit 1

}

# check if zenity must be installed or text terminal can be used

# if fails = script exit

# to install zenity, run: ./script.sh --gui in X terminal

# ask user to confirm install if able to ask

check_gui() {

  local msg="Use terminal or install zenity for gui. '$ sudo apt install zenity'"

  local cmd="sudo apt install zenity"

  local notfirst=$1

  if ! have_command zenity;then

    notify_user "$msg" "error"

    # --gui set and input/output from terminal possible

    if [[ "${gui_set}" && "${start_in_terminal}" ]]; then

      read -p "Install zenity for you? sudo required.[y/N]" -r autozenity

      reg="^[yY]$"

      if [[ "$autozenity" =~ $reg ]]; then

        $(install_zenity "$cmd") || exit

        exit 0

      else

        exit 1

      fi

    else

      if [[ "${gui_set}" ]]; then

        $(install_zenity "$cmd") || exit

        exit 0

      else

        if ! in_terminal;then

          $(install_zenity "$cmd") || exit

          exit 0

        fi

      fi

    fi



  fi

  exit 0

}

$(check_gui) || exit





validate_input() {

  local msg="$1"

  local var="$2"

  local reg=$3

  if ! [[ "$var" =~ $reg ]]; then

    notify_user "$msg" "error"

    exit 1

  fi

  exit 0

}



validate_domain() {

  $(LANG=C; validate_input "Bad domain with leading . (dot)" "$1" 

    "^.[a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9.])*$") || exit 1

  exit 0

}



validate_username() {

  $(LANG=C; validate_input "Bad username." "$1" 

    "^[[:lower:]_][[:lower:][:digit:]_-]{2,15}$") || exit 1

  if ! id "$1" >/dev/null 2>&1; then

    notify_user "User not exists" "error"

    exit 1

  fi

  exit 0

}



validate_group() {

  getent group "$1" > /dev/null 2&>1

  [ $? -ne 0 ] && notify_user "Group $1 not exists" "error" && exit 1

  exit 0

}



validate_email() {

  $(LANG=C; validate_input "Bad admin email." "$1" 

    "^[a-z0-9!#$%&'*+/=?^_`{|}~-]+(.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@([a-z0-9]([a-z0-9-]*[a-z0-9])?.)*[a-z0-9]([a-z0-9-]*[a-z0-9])?$")     || exit 1

  exit 0

}



validate_subdomain() {

  $(LANG=C; validate_input "Bad subdomain" "$1" 

    "^[a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?$") || exit 1

  exit 0

}



getopt --test > /dev/null

if [ "$?" -gt 4 ];then

  echo 'I’m sorry, `getopt --test` failed in this environment.'

else

  OPTIONS="w:d:a:ghi"

  LONGOPTS="webmaster:,domain:,adminemail:,gui,help,webroot:,webgroup:,install,subdomain:,skipmysql,mysqlauto"

  ! PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "$0" -- "$@")

  if [[ ${PIPESTATUS[0]} -ne 0 ]]; then

    # e.g. return value is 1

    # then getopt has complained about wrong arguments to stdout

    exit 2

  fi

  # read getopt’s output this way to handle the quoting right:

  eval set -- "$PARSED"

  while true; do

    case "$1" in

        "--skipmysql")

            skipmysql=1

            shift

            ;;

        "--mysqlauto")

            mysqlauto=1

            shift

            ;;

        "-w"|"--webmaster")

            webmaster="$2"

            webmaster_set=1

            shift 2

            ;;

        "--webgroup")

            webgroup="$2"

            webgroup_set=1

            shift 2

            ;;

        "--subdomain")

            host="$2"

            host_set=1

            shift 2

            ;;

        "-d"|"--domain")

            maindomain="$2"

            maindomain_set=1

            shift 2

            ;;

        "-a"|"--adminemail")

            serveradmin="$2"

            serveradmin_set=1

            shift 2

            ;;

        "--webroot")

            declare -i webroot="$2"

            webroot_set=1

            shift 2

            ;;

        "-g"|"--gui")

            if [ -z "$DISPLAY" ];then

              notify_user "GUI failed. No DISPLAY." "error"

              exit 1

            else

              gui_set=1

              # GUI can be enabled at this point, when run from terminal /

              # with --gui, so check again

              $(check_gui) || exit

              in_terminal() {

                false

              }

            fi

            shift

            ;;

        "-i"|"--install")

            install_set=1

            shift

            ;;

        "-h"|"--help")

            cat << EOF

usage: ./${0}                    # if some arguments specified in command

                                 # line, script will not ask to input it value

                                 # --install of script makes some values predefined

       [--webmaster="userlogin"] # user with permissions to edit www

                                 # files. group is 'www-data'

       [--webgroup="www-data"]   # group of apache2 service user

       [--domain=".localhost"]   # leading dot required

       [--subdomain="Example"]   # Subdomain and webroot folder name

                                 # (folder case censetive)

       [--adminemail="admin@localhost"]

       [--webroot="0"]           # documentroot of virtualhost, zero based index

       # webroots[0]="/home/${webmaster}/Web/${subdomain}"

       # webroots[1]="/var/www/${subdomain}"

       # webroots[2]="/var/www/${webmaster}/${subdomain}"

       [--skipmysql]             # don't create mysql db and user

       [--mysqlauto]             # use subdomain as mysql db name, username, empty password

       [--gui]                   # run gui version from terminal else be autodetected without this.

                                 # attemps to install zenity



       ${0}

       --help                    # this help



       ${0}

       --gui --install           # install .desktop shortcut for current user

                                 # and optionally copy script to $home/bin

                                 # --install requires --gui

                                 # shortcut have few options to run, without mysql for example

       ${0} "without arguments"  # will read values from user

EOF

            exit 0

            ;;

        --)

            shift

            break

            ;;

        *)

            echo "Error" >&2

            exit 3

            ;;

    esac

  done

  if [ "$install_set" ]; then

    ! [ "$gui_set" ] && notify_user "--gui must be set with --install" && exit 1

    homedir=$( getent passwd "$(id -un)" | cut -d: -f6 )



    source="${BASH_SOURCE[0]}"

    while [ -h "$source" ]; do # resolve $SOURCE until the file is no longer a symlink

      dir="$( cd -P "$( dirname "$source" )" >/dev/null 2>&1 && pwd )"

      source="$(readlink "$source")"

      [[ $source != /* ]] && source="$dir/$source"

      # ^ if $SOURCE was a relative symlink, we need to resolve it relative to

      # the path where the symlink file was located

    done

    dir="$( cd -P "$( dirname "$source" )" >/dev/null 2>&1 && pwd )"

    scriptname=$( basename "$source" )



    # make a form where script args can be predefined, so not needed every launch

    pipestring=$(zenity --forms --add-entry="Domain(leading dot)(Default .localhost)" 

      --add-entry="Webmaster(default: current username)" 

      --add-entry="Webgroup(Default: www-data)" 

      --add-entry="Server admin(Default: webmaster@localhost)" 

      --text="Predefined values(empty=interactive edit)" --title="Desktop shortcut" 

      --add-combo="Install path" --combo-values="${homedir}/bin/|${dir}/" 2>/dev/null)



    # zenity stdout if like value1|value2|etc

    IFS='|' read -r -a form <<< "$pipestring"

    args=""

    if [ "${form[0]}" ]; then $(validate_domain "${form[0]}") || exit 60; fi

    if [ "${form[1]}" ]; then $(validate_username "${form[1]}") || exit 61; fi

    if [ "${form[2]}" ]; then $(validate_group "${form[2]}") || exit 62; fi

    if [ "${form[3]}" ]; then $(validate_email "${form[3]}") || exit 63; fi

    if [ "${form[4]}" ]; then mkdir -p "${form[4]}"; fi



    [ "${form[0]}" ] && args="$args --domain='${form[0]}'"

    [ "${form[1]}" ] && args="$args --webmaster='${form[1]}'"

    [ "${form[2]}" ] && args="$args --webgroup='${form[2]}'"

    [ "${form[3]}" ] && args="$args --adminemail='${form[3]}'"

    installpath="${dir}/${scriptname}"

    if [ "${form[4]}" != " " ]; then installpath="${form[4]}${scriptname}"; fi



    cp "${dir}/${scriptname}" "$installpath" >/dev/null 2>&1

    chmod u+rx "$installpath"



    desktop="$homedir/.local/share/applications/virtualhost.desktop"

    cat >"$desktop" <<EOF

[Desktop Entry]

Version=1.0

Name=Create Virtualhost

Comment=Easy to create new virtualhost for apache2 server

Keywords=Virtualhost;Apache;Apache2

Exec=/bin/bash ${installpath} ${args}

Terminal=false

X-MultipleArgs=true

Type=Application

Icon=network-wired

Categories=GTK;Development;

StartupNotify=false

Actions=without-arguments;new-install



[Desktop Action without-arguments]

Name=Clean launch

Exec=/bin/bash ${installpath}



[Desktop Action without-mysql]

Name=Without mysql config

Exec=/bin/bash ${installpath} ${args} --skipmysql



[Desktop Action new-install]

Name=Reinstall (define new configuration)

Exec=/bin/bash ${installpath} --install --gui

X-MultipleArgs=true

EOF



    exit 0

  fi



  # if arguments passed - validate them.

  msg=""

  if [ "$maindomain_set" ]; then

    $(validate_domain "$maindomain") 

      || msg="Bad value for --domain. Should have leading dot.  ".localhost"n"

  fi

  if [ "$serveradmin_set" ]; then

    $(validate_email "$serveradmin") || msg="Bad value for --adminemailn$msg"

  fi

  if [ "$host_set" ]; then

    $(validate_subdomain "$host") || msg="Bad value for --subdomainn$msg"

  fi

  if [ "$webmaster_set" ]; then

    $(validate_username "$webmaster") || msg="Bad value for --webmastern$msg"

  fi

  if [ "$webgroup_set" ]; then

    $(validate_group "$webgroup") || msg="Bad value for --webgroupn$msg"

  fi

  have_command apache2 || msg="Apache2 not installedn$msg"

  if [ "$msg" ];then

    [ "$gui_set" ] && info_user "$msg" "error"

    exit 1

  fi

fi



if [ "$(id -un)" == "root" ];then

   notify_user "You should not run this script as root but as user with 'sudo' rights." "error"

   exit 1

fi



get_text_input() {

    if in_terminal; then

        defaulttext=""

        [ "$3" ] && defaulttext="[Default: ${3}]"

        read -p "${2}$defaulttext" -r input

        # default

        [ "$3" ] && [ -z "$input" ] && input="$3"

    else

       input=$(zenity --entry="$1" --title="Virtualhost" --text="$2" --entry-text="$3" 2>/dev/null)

       if [ "$?" == "1" ]; then

         echo "[$1]Cancel button" 1>&2

         exit 1     # Cancel button pressed

     fi

    fi

    if [ -z "$4" ]; then

      case "$input" in

          "")            notify_user "[$1]Bad input: empty" "error" ;      exit 1 ;;

          *"*"*)         notify_user "[$1]Bad input: wildcard" "error" ;   exit 1 ;;

          *[[:space:]]*) notify_user "[$1]Bad input: whitespace" "error" ; exit 1 ;;

      esac

    fi

    echo "$input"

}



# get input and validate it

if [ -z "$host" ]; then host=$(get_text_input "Subdomain" "Create virtualhost (= Folder name,case sensitive)" "") || exit; fi

$(validate_subdomain "$host") || exit



if [ -z "$maindomain_set" ]; then maindomain=$(get_text_input "Domain" "Domain with leading dot." "$maindomain") || exit; fi

$(validate_domain "$maindomain") || exit



if [ -z "$webmaster_set" ]; then webmaster=$(get_text_input "Username" "Webmaster username" "$webmaster") || exit; fi

$(validate_username "$webmaster") || exit



if [ -z "$serveradmin_set" ]; then serveradmin=$(get_text_input "Admin email" "Server admin email" "$serveradmin") || exit; fi

$(validate_email "$serveradmin") || exit



homedir=$( getent passwd "$webmaster" | cut -d: -f6 )

# webroot is a choise of predefined paths array

declare -a webroots=("${homedir}/Web/${host}" "/var/www/${host}" "/var/www/${webmaster}/${host}")

zenitylistcmd=""

# zenily list options is all columns of all rows as a argument, one by one

for (( i=0; i<${#webroots[@]}; i++ ));do

  if in_terminal; then

    echo "[${i}] ${webroots[$i]}" # reference for text read below

  else

    zenitylistcmd="${zenitylistcmd}${i} ${i} ${webroots[$i]} "

  fi

done

dir=""

[ -z "$webroot_set" ] && if in_terminal; then

  webroot=$(get_text_input 'Index' 'Website folder' "$webroot") || exit

else

  webroot=$(zenity --list --column=" " --column="Idx" --column="Path" --hide-column=2 

    --hide-header --radiolist --title="Choose web folder" $zenitylistcmd 2>/dev/null)

fi

if [ -z "${webroots[$webroot]}" ]; then notify_user "Invalid webroot index"; exit 1; fi



dir="${webroots[$webroot]}"          # folder used as document root for virtualhost

hostfile="${apachehost}${host}.conf" # apache virtualhost config file



# virtualhost template

cat >"$tmphost" <<EOF

<VirtualHost ${virtualhost}:${virtualport}>

    ServerAdmin $serveradmin

    DocumentRoot $dir

    ServerName  ${host}${maindomain}

    ServerAlias ${host}${maindomain}

    <Directory "$dir">

      AllowOverride All

      Require local

    </Directory>

    # Available loglevels: trace8, ..., trace1, debug, info, notice, warn,

    # error, crit, alert, emerg.

    LogLevel error

</VirtualHost>

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

EOF



find_editor() {

  local editor=${VISUAL:-$EDITOR}

  if [ "$editor" ]; then

    echo "$editor"

    return

  fi



  for cmd in nano vim vi pico; do

    if have_command "$cmd"; then

      echo "$cmd"

      return

    fi

  done

}



if in_terminal; then

  # edit virtualhost config

  editor=$(find_editor)

  if [ -z "$editor" ];then

      echo "$tmphost:"

      cat  $tmphost

      echo "edit '$tmphost' to your liking, then hit Enter"

      read -p "I'll wait ... "

  else

      "$editor" "$tmphost"

  fi

else

  # edit virtualhost config GUI

  text=$(zenity --text-info --title="Virtualhost config" --filename="$tmphost" --editable 2>/dev/null)

  if [ -z "$text" ];then

    # cancel button pressed

    exit 0

  fi

  echo "$text" > "$tmphost"

fi

# probably want some validating here that the user has not broken the config

# apache will not reload config if incorrect



mysqlskip="$skipmysql"  # skip if --skipmysql set

[ -z "$mysqlskip" ] && if have_command mysqld; then

  if [ -z "$mysqlskip" ]; then mysqladminpwd=$(get_text_input "Admin password" "Admin password (${mysqladmin})" "" "skipcheck") || mysqlskip=1; fi

  if [ "$mysqlauto" ]; then

    mysqldb="$host"

    mysqluser="$host"

    mysqlpwd=""

  else

    if [ -z "$mysqlskip" ]; then

      mysqldb=$(get_text_input "Database" "Database name(Enter for default)" "$host") || mysqlskip=1

    fi

    if [ -z "$mysqlskip" ]; then

      mysqluser=$(get_text_input "Username" "Mysql user for db:$mysqldb host:localhost(Enter for default)" "$mysqldb") || mysqlskip=1

    fi

    if [ -z "$mysqlskip" ]; then

      mysqlpwd=$(get_text_input "Password" "Mysql password for user:$mysqluser db:$mysqldb host:localhost(Enter for empty)" "" "skipcheck") || mysqlskip=1

    fi

  fi



  if [ -z "$mysqlskip" ]; then

    tmpmysqlinit=$(mktemp)

    trap 'rm "$tmpmysqlinit"' EXIT

    cat >"$tmpmysqlinit" <<EOF

CREATE USER '${mysqluser}'@'localhost' IDENTIFIED BY '${mysqlpwd}';

GRANT USAGE ON *.* TO '${mysqluser}'@'localhost';

CREATE DATABASE IF NOT EXISTS `${mysqldb}` CHARACTER SET utf8 COLLATE utf8_general_ci;

GRANT ALL PRIVILEGES ON `${mysqldb}`.* TO '${mysqluser}'@'localhost';

FLUSH PRIVILEGES;

EOF

  fi

fi



getsuperuser () {

  if in_terminal;then

    echo "sudo"

  else

    echo "pkexec"

  fi

}



notify_user "execute root commands with $(getsuperuser) to create virtualhost" "warning"



tmpresult=$(mktemp)

trap 'rm "$tmpresult"' EXIT

tmpmysqlresult=$(mktemp)

trap 'rm "$tmpmysqlresult"' EXIT



$(getsuperuser) /bin/bash <<EOF

mkdir -p "$dir"

chown ${webmaster}:${webgroup} "$dir"

chmod u=rwX,g=rXs,o= "$dir"

cp "$tmphost" "$hostfile"

chown root:root "$hostfile"

chmod u=rw,g=r,o=r "$hostfile"

a2ensite "${a2ensite}${host}.conf"

systemctl reload apache2

echo "$?" > "$tmpresult"

if [ -z "${mysqlskip}" ]; then

  systemctl start mysql

  mysql --user="$mysqladmin" --password="$mysqladminpwd" <"$tmpmysqlinit"

  echo "$?" > "$tmpmysqlresult"

fi

EOF



if [ $(cat "$tmpmysqlresult") ]; then $mysqlresult="nMysql db,user created"; fi

if [ $(cat "$tmpresult") ]; then notify_user "Virtualhost added. Apache2 reloaded.${mysqlresult}"; fi

As bash scripts go, this is well done. You've made pretty good use of bash features and the code clearly reflects time spent debugging and refining.

There are two big things I would do differently:

1. I wouldn't use bash. As the number of code paths and lines of code increase, access to a real debugger and static syntax checking outweigh the convenience of a shell.


2. I'd separate the heavy lifting from the GUI. A lot of the complexity and sheer bulk of this script arises from its constant jumping between performing the task and checking in with the user. Develop a solid non-interactive tool, then build a GUI on top of it.

What's done is done, though, and here are some changes I'd recommend to the code as-is:

refactor the death pattern

There's a lot of code like this:

if [ -z "$DISPLAY" ];then

    notify_user "GUI failed. No DISPLAY." "error"

    exit 1

fi

That could be shortened by using an error-handling function:

[ -n $DISPLAY ] || die "GUI failed. No DISPLAY."

This makes it easy to add cleanup or other functionality to fatal errors. The function can be as simple as:

die() {

    notify_user "$1" "${2:-error}"

    exit ${3:-1}

}

tempfiles considered harmful

Most tempfile contents are better stored in a variable. Variables avoid all kinds of failure modes—disk full, no permission, file deleted from /tmp by cleanup job—and save you having to worry about if anyone can read the password saved in the mysql temp file.

The only real drawback is that you're limited by memory; variables are unsuitable for gigabytes of data.

mysqlinit="CREATE USER '${mysqluser}'@'localhost' IDENTIFIED BY '${mysqlpwd}';

GRANT USAGE ON *.* TO '${mysqluser}'@'localhost';

CREATE DATABASE IF NOT EXISTS `${mysqldb}` CHARACTER SET utf8 COLLATE utf8_general_ci;

GRANT ALL PRIVILEGES ON `${mysqldb}`.* TO '${mysqluser}'@'localhost';

FLUSH PRIVILEGES;"

…

mysql --user="$mysqladmin" --password="$mysqladminpwd" <<<$mysqlinit

If the quoting is hairy, you can cat a heredoc and capture with $( … ):

foo=$( 

    cat <<EOF

…

EOF

)

find_editor() could be a lot shorter

Instead of:

find_editor() {

  local editor=${VISUAL:-$EDITOR}

  if [ "$editor" ]; then

    echo "$editor"

    return

  fi



  for cmd in nano vim vi pico; do

    if have_command "$cmd"; then

      echo "$cmd"

      return

    fi

  done

}

Just:

find_editor() { 

    type -P $VISUAL $EDITOR nano vim vi pico | head -1

}

refactor the "if I have" pattern

Instead of:

if have_command zenity; then

    zenity --notification --text="${prefix}$1" --window-icon="$windowicon"

    return

fi

How about:

try() { 

    have_command "$1" && "$@"

}

…

try zenity --notification --text="${prefix}$1" --window-icon="$windowicon" && return

check for errors

What happens if cp "${dir}/${scriptname}" "$installpath" only copies half of the script before the disk fills up? Probably nothing good.

Consider set -e to have bash terminate on error. It's going to be a bit of work, because you'll need to mask ignorable errors (usually by adding || true to the command). The benefit comes when you get to the end of the script and start doing system configuration, you know that there isn't some early error messing everything up.

some of these $( ) invocations are weird

You have a bunch of $(function) as the first argument on a command line, which runs the output of function as a second command. That's hacky but kind-of okay, except function doesn't produce any output. So it's just weird and it's going to break if function ever writes anything to stdout.

If you want to contain the effects of an exit, use plain () without the dollar sign. Better yet, use return in the function, instead of exit, and omit the parens altogether.

little stuff

$(LANG=C; validate_input "Bad subdomain" "$1" 

    "^[a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?$") || exit 1

A domain can't start with a digit. If this is for internal use, consider disallowing caps (or folding them to lowercase).

>& /dev/null is bash shorthand for > /dev/null 2>&1.

args="$args --domain='${form[0]}'" can be replaced by args+=" --domain=${form[0]}"

Declare your read-only globals as such (declare -r x=y) to avoid accidentally clobbering them.

Some suggestions:

• Because of length and complexity alone I would say Bash is not a good fit for this purpose. A language like Python will be much better at validating strings, argument parsing, escaping SQL and especially error handling. Case in point:


• 
  

  Your traps are clobbering each other. See this example:

  
  
  

  $ trap echo EXIT
  
  $ trap ls EXIT
  
  $ trap -p
  
  trap -- 'ls' EXIT
  
  

  
  


• ".localhost" is not a domain - "localhost" is, and the dot is the separator between the hostname and domain.


• The exit trap should be set up before creating the temporary directory, to avoid a race condition.


• 
  Shell scripts should not be interactive unless absolutely required (such as top or vim). Instead of asking the user to install some software I would make Zenity an optional dependency of this script, and possibly warn the user about it being missing if necessary. This will shorten and simplify your script considerably.


• 
  Shell scripts should not run sudo (or equivalent). Privilege escalation should always be at the discretion of the user, so the script should simply fail with a useful message if it can't do what it needs to because of missing privileges.


• 
  notify_user could just as well echo "$@" to support any number of arguments, or could also include useful information such as the time of the message if you use printf instead.


• A more portable shebang line is #!/usr/bin/env bash.


• 
  Use [[ rather than [.


• Run the script through shellcheck to get more linting tips.