Check single character in array bash for password generator - arrays

Question

I am trying to test User input with password rules.
must be at least 8 characters long but not longer than 16 characters.
must contain at least 1 digit (0-9).
must contain at least 1 lowercase letter.
must contain at least 1 uppercase letter.
must contain exactly one and only one of #, #, $, %, &, *, +, -, =.
I'm trying to figure how I can compare the user string to the arrays that contain the password characters.
#!/bin/bash
Upper=("A""B""C""D""E""F""G""H""I""J""K""L""M""N""O""P""Q""R""S""T""U""V""W""X""Y""Z")
Lower=("a""b""c""d""e""f""g""h""i""j""k""l""m""o""p""q""r""s""t""u""v""w""x""y""z")
Numbers=("1""2""3""4""5""6""7""8""9")
SpecialChar=("&""#""#""$""%""*""-""+""=")
# Password Generator
PassGen(){ # generate password if no user input
Pwlength=`shuf -i 8-16 -n 1` # holds the range/length of password
Password=`< /dev/urandom tr -dc A-Za-z0-9$SpecialChar | head -c $Pwlength`
echo "Random Password is being generated for you"
sleep 5
echo "Your new password is : $Password"
echo exit?
}
# I want to make the following to work :
\#PassGen2(){ # generate password 2 if no user input
\#if [ $# -eq 0 ] ; then
\#for ((i=0;i<4;i++))
\#do
\#password="${Upper[$random % ${#Upper[#]}" ] }
\#password="${Lower[$random % ${#Lower[#]}" ] }
\#password="${Numbers[$random % ${#Numbers[#]}" ] }
\#done
\#password="${SpecialChar[$random % ${#SpecialChar[#]}" ] }
\#password="${Upper[$random % ${#Upper[#]}" ] }
\#echo "Random Password is being generated for you"
\#sleep 5
\#echo "Your new password is : $Password"
\#fi
\#echo exit?
\#}
# Help menu
Usage(){ # Help menu
echo "The password must meet the following :"
echo "> must be at least 8 characters long but not longer than 16 characters."
echo "> must contain at least 1 digit (0-9)."
echo "> must contain at least 1 lowercase letter."
echo "> must contain at least 1 uppercase letter."
echo "> must contain exactly one and only one of # # $ % & * + - ="
echo ""
echo " * * IF NO PASSWORD IS ENTERED THE SYSTEM WILL GENERATE A PASSPORD FOR YOU * * "
echo exit?
}
#The main starts here
if [ $# -eq 0 ] ; then
PassGen $SpecialChar
fi
if [ $# == "-h"] ; then
Usage
fi
UserPW=$1 # assigning the firsth positional parameter to variable (password)
#The reason I open the post
PwCheck(){
if [[ ${#UserPW} < 8 && ${#UserPW} > 0 ]] ;then #check the lower end of the password
echo "Password have to be more then 8 character"
exit 1
fi
if [[ ${#UserPW} < 16 ]] ;then #checks if the password bigger then 16 character
echo "Password too long ! - Password have to be between 8 - 16 characters"
exit 1
fi
if [[ ${#UserPW} < 17 && ${#UserPW} > 8 ]] ; then
Pwarr=($UserPW) # putting the variable into Array
for (( i=0; i < ${#Upper[#]};i++ ))
do
if [[ ${Pwarr[0]:[i]:1} != ${Upper[i]} ]]; then
echo "You have to enter at least 1 upper character letter"
exit 1
fi
done
for (( i=0; i < ${#Lower[#]};i++ ))
do
if [[ ${Pwarr[0]:[i]:1} != ${Lower[i] ]]; then
echo "You have to enter at least 1 Lower character letter"
exit 1
fi
done
for (( i=0; i < ${#SpecialChar[#];i++ ))
do
if [[ ${Pwarr[0]:[i]:1} != ${SpecialChar[i] ]] ;then
echo " You have to enter at least 1 special character
exit 1
fi
done
#}
My problems:
I couldn't make my PassGen2() to work beside "calling it". I know
there must be typo or syntax errors.
For PwCheck() function I know I didn't call it and the IF
statement should be in the main section.

Answer 1

It's easier to implement PwCheck leaving the user password as a string rather than converting it to an array:
bad_length(){
l=`wc -c`
[ $l -ge 8 ] && [ $l -le 16 ] && return 1 || return 0
}
no_digit(){
grep -q '[0-9]' && return 1 || return 0
}
no_lc(){
grep -q '[a-z]' && return 1 || return 0
}
no_uc(){
grep -q '[A-Z]' && return 1 || return 0
}
specials='##$%&*+=-'
no_exactly_one_special(){
n=`grep -o "[$specials]" | wc -l`
[ $n -eq 1 ] && return 1 || return 0
}
echo "$1" | bad_length && echo 'Password must be between 8 - 16 characters' && exit 1
echo "$1" | no_digit && echo 'Password must have at least one number 0-9' && exit 1
echo "$1" | no_lc && echo 'Password must have at least one lowercase letter' && exit 1
echo "$1" | no_uc && echo 'Password must have at least one UPPERCASE letter' && exit 1
echo "$1" | no_exactly_one_special && echo "Password must have exactly one special character: $specials" && exit 1
exit 0
A few words of explanation:
First, it is possible in bash to pipe (using |) to a function:
no_digit_from_stdin(){
grep -q '[0-9]' && return 1 || return 0
}
echo "abc" | no_digit_from_stdin && echo $?
instead of passing it as an argument:
no_digit_from_arg(){
echo "$1" | grep -q '[0-9]' && return 1 || return 0
}
no_digit_from_arg "abc" && echo $?
These two have the same outcome here.
Second, it is possible to use pipes and && to control flow concisely. So this:
echo "$1" | no_digit_from_stdin && echo 'Password must have at least one number 0-9' && exit 1
has the same outcome as this:
if no_digit_from_arg "$1"; then
echo 'Password must have at least one number 0-9'
exit 1
fi
...but these are matters of style and not directly relevant to your question.
Here is a version of my answer that you may find more usable, with a secret bonus feature:
PwCheck(){
pass=true
l=`echo "$UserPW" | wc -c`
if [ $l -lt 8 ] || [ $l -gt 16 ]; then
echo 'Password must be between 8 - 16 characters'
pass=false
fi
if ! echo "$UserPW" | grep -q '[0-9]'; then
echo 'Password must have at least one number 0-9'
pass=false
fi
if ! echo "$UserPW" | grep -q '[a-z]'; then
echo 'Password must have at least one lowercase letter'
pass=false
fi
if echo "$UserPW" | grep -q '[A-Z]'; then
echo 'Password must have at least one UPPERCASE letter'
pass=false
fi
specials='##$%&*+=-'
n=`echo "$UserPW" | grep -o "[$specials]" | wc -l`
if [ $n -ne 1 ]; then
echo "Password must have exactly one special character: $specials"
pass=false
fi
if $pass; then
exit 0
else
exit 1
fi
}