bash/snippets/create_shadow_paswd.sh

#!/usr/bin/env bash

script_name="$(basename $(realpath $0))"
working_dir="$(dirname $(realpath $0))"

conf_file="${working_dir}/conf/${script_name%%.*}.conf"

LOCK_DIR="/tmp/$(basename $0).$$.LOCK"
log_file="${LOCK_DIR}/${script_name%%.*}.log"


# ----------
#  Script settings
# ----------

# - Give your default values here
# -
SALT_LENGTH=8


# ----------
# Base Function(s)
# ----------

usage() {


   [[ -n  "$1" ]] && error "$1"


   [[ $terminal ]] && echo -e "
\033[1mUsage:\033[m

   $(basename $0) 

\033[1mDescription\033[m

   Script creates a saltet SHA-512 password hash for use in '/etc/shadow'. 
   The length of salt is '8'.

\033[1mOptions\033[m

   No Options needed. The clear password will be asked for.

\033[1mFiles\033[m

   No configuration files needed

\033[1mExample:\033[m
   
   Create a saltet SHA512 password hash

      $(basename $0)

"

   clean_up 1

}

clean_up() {

   # Perform program exit housekeeping
   rm -rf "$LOCK_DIR"
   blank_line
   exit $1
}


echononl(){
   if $terminal ; then
      echo X\\c > /tmp/shprompt$$
      if [ `wc -c /tmp/shprompt$$ | awk '{print $1}'` -eq 1 ]; then
         echo -e -n "   $*\\c" 1>&2
      else
         echo -e -n "   $*" 1>&2
      fi
      rm /tmp/shprompt$$
   fi
}


fatal(){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[31m\033[1mFatal\033[m ] $*"
   else
      echo -e "   [ Fatal ] $*"
   fi
   echo ""
   if $terminal ; then
      echo -e "             \033[1mScript terminated\033[m.."
   else
      echo -e "             Script terminated.."
   fi
   echo ""
   rm -rf $LOCK_DIR
   exit 1
}

error (){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[31m\033[1mError\033[m ] $*"
   else
      echo "   [ Error ] $*"
   fi
   echo ""
}

warn (){
   if $LOGGING || $terminal ; then
      echo ""
      if $terminal ; then
         echo -e "   [ \033[33m\033[1mWarn\033[m ]  $*"
      else
         echo "   [ Warn ]  $*"
      fi
      echo ""
   fi
}

info (){
   if $LOGGING || $terminal ; then
      echo ""
      if $terminal ; then
         echo -e "   [ \033[32m\033[1mInfo\033[m ]  $*"
      else
         echo "   [ Info ]  $*"
      fi
      echo ""
   fi
}

ok (){
   if $LOGGING || $terminal ; then
      echo ""
      if $terminal ; then
         echo -e "   [ \033[32m\033[1mOk\033[m ]    $*"
      else
         echo "   [ Ok ]    $*"
      fi
      echo ""
   fi
}

echo_done() {
   if $terminal ; then
      echo -e "\033[75G[ \033[32mdone\033[m ]"
   fi
}
echo_ok() {
   if $terminal ; then
      echo -e "\033[75G[ \033[32mok\033[m ]"
   fi
}
echo_failed(){
   if $terminal ; then
      echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
   fi
}
echo_skipped() {
   if $terminal ; then
      echo -e "\033[75G[ \033[33m\033[1mskipped\033[m ]"
   fi
}
echo_wait(){
   if $terminal ; then
      echo -en "\033[75G[ \033[5m\033[1m...\033[m ]"
   fi
}

trim() {
    local var="$*"
    var="${var#"${var%%[![:space:]]*}"}"   # remove leading whitespace characters
    var="${var%"${var##*[![:space:]]}"}"   # remove trailing whitespace characters
    echo -n "$var"
}

blank_line() {
   if $terminal ; then
      echo ""
   fi
}



# ----------
# - Jobhandling 
# ----------

# - Run 'clean_up' for signals SIGHUP SIGINT SIGTERM
# -
trap clean_up SIGHUP SIGINT SIGTERM

# - Create lock directory '$LOCK_DIR"
#
mkdir "$LOCK_DIR"


# ----------
# - Some checks ..
# ----------

# - Running in a terminal?
# -
if [[ -t 1 ]] ; then
   terminal=true
else
	fatal "Script must run in a terminal."
fi

# - Print help?
# -
if [[ "$(trim $*)" = "-h" ]] || [[ "$(trim $*)" = "--help" ]] ; then
    usage
fi

if [[ -z "$(which basename)" ]]; then
   fatal 'It seems "basename" is not installed, but needed!'
fi

if [[ -z "$(which realpath)" ]]; then
   fatal 'It seems "realpath" is not installed, but needed!'
fi


# ==========
# - Begin Main Script
# ==========

# ----------
# - Headline
# ----------

if $terminal ; then
   echo ""
   echo -e "\033[1m----------\033[m"
   echo -e "\033[32m\033[1mRunning script \033[m\033[1m$script_name\033[32m .. \033[m"
   echo -e "\033[1m----------\033[m"
fi


# ----------
# - Read in parameters given by user
# ----------

echo ""
echo -e "   \033[32m--\033[m"
echo ""
echo "   Insert the password for which the password hash should be created."
echo ""
echo ""
_CLEAR_PASSWD_1="X"
_CLAER_PASSWD_2="Y"
while [[ "$_CLEAR_PASSWD_1" != "$_CLEAR_PASSWD_2" ]] ; do

	echononl "\033[1mPassword :\033[m "
	read -s _CLEAR_PASSWD_1

	blank_line

	if [[ "X$_CLEAR_PASSWD_1" = "X" ]]; then
		echo -e "\n   \033[33m\033[1mA password is required!\033[m\n"
		continue
	fi

	echononl "\033[1mRepeat password:\033[m "
	read -s _CLEAR_PASSWD_2

	if [[ "$_CLEAR_PASSWD_1" != "$_CLEAR_PASSWD_2" ]]; then
		echo -e "\n\n   \033[33m\033[1mPasswords did not match!\033[m\n"
	else
		CLEAR_PASS="$_CLEAR_PASSWD_1"
	fi

done

echo ""
echo ""
echononl "Print a summary including the clear password? [\033[1myes/no\033[m]: "
read OK
while [[ "${OK,,}" != "yes" ]] && [[ "${OK,,}" != "no" ]] ; do
	echononl "\033[33mWrong entry!\033[m [\033[1myes/no\033[m]: "
	read OK
done

if [[ "${OK,,}" = "yes" ]] ; then
	echo ""
	echo ""
	echo -e "   \033[32m\033[1mParameter Summary:\033[m"
	echo ""

	echo "   Clear password.............: $CLEAR_PASS"

	echo ""
	echononl "Continue with this parameters? [\033[1myes/no\033[m]: "
	read OK
	while [[ "${OK,,}" != "yes" ]] && [[ "${OK,,}" != "no" ]] ; do
		echononl "\033[33mWrong entry!\033[m [\033[1myes/no\033[m]: "
		read OK
	done
	[[ "${OK,,}" = "yes" ]] || fatal "Canceled by user input."
fi



# ----------
# - Some pre-script tasks ..
# ----------


# ----------
# - Main part of script
# ----------

SALTED_HASH="$(mkpasswd  -m sha-512 -S "$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w $SALT_LENGTH | head -n 1)" -s <<< $CLEAR_PASS)"


echo ""
info "Salted SHA512 password hash:"

echo -e "\t\033[1m${SALTED_HASH}\033[m\n"

clean_up 0