I have this piece of code in PowerShell. I need user input validation to integer with writing output saying what is wrong with the input and expecting correct input.
$FromObj = "Please input object number"
$FromInput = Read-Host $FromObj
while(($FromInput -isnot [int])) {
#I also want to put in the while that the input has to be an integer, -gt 0, and -lt 800
Write-Output "Your input has to be a number."
$FromInput = Read-Host $FromObj
}
if ($FromInput -le 0) {
Write-Output "Your input has to be a number greater than 0!"
$FromInput = Read-Host $FromObj
}
elseif ($FromInput -ge 800) {
Write-Output "Your input has to be a number less than 800!"
$FromInput = Read-Host $FromObj
}
else {
$FromInput = $FromInput -as [int]
}
However, this is not working for me. Could you help me with validating it with writing outputs as the ones displayed above?
I think Nicks's link in comment already provides different right answers to your question i.e.: using regex to match \d+ (digits) or using [int]::TryParse(...) but to explain why your code is not working:
Read-Host will store user input as string unless you manipulate it which is what you were already doing on your last condition (the else {...} statement).
This is why you never get past the $FromInput -isnot [int] condition.
To fix the code you could simply attempt to store user input -as [int] since the beginning and since you have 3 Read-Host on your code you could save the user input attempt -as [int] in a ScriptBlock which then can be easily executed as many times as needed:
$FromObj = "Please input object number"
$giveMeNumber = { (Read-Host $FromObj) -as [int] }
$FromInput = & $giveMeNumber
while($FromInput -isnot [int]) {
Write-Output "Your input has to be a number."
$FromInput = & $giveMeNumber
}
if ($FromInput -le 0) {
Write-Output "Your input has to be a number greater than 0!"
$FromInput = & $giveMeNumber
}
elseif ($FromInput -ge 800) {
Write-Output "Your input has to be a number less than 800!"
$FromInput = & $giveMeNumber
}
Note, even though this works, the statement is not entirely correct since you're breaking out of the while loop after the input is [int] the user could force an incorrect input.
Try this instead which will execute indefinitely until right input:
Clear-Host
$ErrorActionPreference = 'Stop'
$FromObj = "Please input object number"
$scriptBlock = {
try
{
$FromInput = [int](Read-Host $FromObj)
# Note I'm using Write-Host instead of Write-Ouput, this is because
# we don't want to store the invalid inputs messages in the
# $userInput variable.
if ($FromInput -le 0) {
Write-Host "Your input has to be a number greater than 0!"
& $scriptBlock
}
elseif ($FromInput -ge 800) {
Write-Host "Your input has to be a number less than 800!"
& $scriptBlock
}
else {
$FromInput
}
}
catch
{
Write-Host "Your input has to be a number."
& $scriptBlock
}
}
$userInput = & $scriptBlock
I'm trying to start my Powershell portfolio with and easy script that calculates Network ID or BroadcastID depending on input from the user. That being said, I can only get my if statement to run. I am unsure what I am missing here. I have tried searching this as I know I cannot be the only one to have this issue, but I am unable to find it. Any education on my error would be appreciated as it seems like a basic flaw.
Thanks!
#prompt for IP and subnet mask
$ip = Read-Host -Prompt "Enter your IP address"
$mask = Read-Host - Prompt "Enter your subnet mask"
[String]$UserDecision = Read-Host -Prompt "Enter N if you would like to calculate your Network ID or B if you would like to calculate your Broadcast address."
$splitmask=$mask.split(".")
$wildcard="$(255 - $splitmask[0]).$(255 - $splitmask[1]).$(255 - $splitmask[2]).$(255 - $splitmask[3])"
# ip and mask variable to ip addresses
$ip = [ipaddress] $ip
$mask = [ipaddress] $mask
#determine networkID
function CalculateNetID {
$networkID = [ipaddress] ($ip.Address -band $mask.Address)
#print NetworkID to console
echo "The Network id is $($networkID.IPAddressToString)"
}
function CalculateBroadcastID {
$networkID = [ipaddress] ($ip.Address -band $mask.Address)
#convert wildcard to IP addresses
$wildcard= [ipaddress] $wildcard
$broadcast = [ipaddress] $($wildcard.Address -bor $NetworkID.Address)
#print broadcast to console
echo "The Broadcast id is $broadcast"
}
if ($UserDecision -eq "N" -or "n"){
CalculateNetID
}
elseif($UserDecision -eq "B" -or "b"){
CalculateBroadcastID
}
else{
echo "Please retry and enter the character associated with the ID you would like to calculate"
}
Here is your problem:
$false -or 'n' # => True
As you can see, this is what's happening in your first if statement, the correct syntax for your condition should be:
if($UserDecision -eq "N" -or $UserDecision -eq "n") {
Same thing applies for the elseif.
Note that, PowerShell comparison operators are not case-sensitive by default, so the -or conditions could be just removed:
if($UserDecision -eq "n") {
You might also want to consider using a switch statement instead of chained if, elseif, else:
switch($UserDecision) {
N { CalculateNetID }
B { CalculateBroadcastID }
Default {
"Please retry and enter the character associated with the ID you would like to calculate"
}
}
What exactly am I doing wrong here, it seems to be subtracting just fine but adding and multiplying seems to not work at all.
How do I get it to do the calculations correct and allow the if statement to also work as it seems to always run even if the numbers are incorrect size.
$a = Read-Host "What is your name?"
$b = Read-Host "Enter a 2 digit number"
$c = Read-Host "Enter a 3 digit number"
if (($b -ge 10) -and ($b -le 99) -and ($c -ge 100) -and ($c -le 999)){
$d = $b + $c
$e = $b * $c
$g = $b - $c
$d
$e
$g
Write-host "Here you go $a"
}
else {
write-host "Enter the numbers correctly"
}
Here the results I get
Read-Host always outputs a string.
In order to treat the output as a number, you must explicitly convert it to one:
$a = Read-Host "What is your name?"
# Note: Add error handling with try / catch
# and a retry loop to deal with invalid input.
[int] $b = Read-Host "Enter a 2 digit number"
[int] $c = Read-Host "Enter a 3 digit number"
The above type-constrains variables $b and $c to integer values (by placing the [int] cast to the left of the target variable in the assignment), which automatically converts Read-Host's [string] output to [int].
To spell it out with a concrete example that prompts until a two-digit (decimal) number is entered:
do {
try {
[int] $b = Read-Host "Enter a 2 digit number"
} catch {
continue # Not a number - stay in the loop to prompt again.
}
if ($b -ge 10 -and $b -le 99) { break } # OK, exit the loop.
} while ($true)
Note: Strictly speaking, the [int] cast accepts anything that would work as a number literal in PowerShell, which includes hexadecimal representations, such as 0xA, as well as number with a type suffix, such as 10l - see this answer for more information.
As for what you tried:
Except for -, all the operators used in your code have string-specific overloads (meaning); note that it is sufficient for the LHS to be of type [string] to trigger this behavior.[1]
-lt / -ge perform lexical comparison with strings; e.g., '10' -gt '2' yields $false, because, in lexical sorting, string '10' comes before string '2'.
-and / -or treat empty strings as $false, and any nonempty string as $true; e.g., '0' -and '0' is $true, because '0' is a nonempty string.
+ performs string concatenation; e.g., '1' + '0' is '10'.
* performs string replication; e.g., '1' * 3 is '111' - the LHS is repeated as many times as specified by the number on the RHS; note that '1' * '3' works the same, because the RHS is coerced to an [int] in this case.
- is the only exception: it always performs a numeric operation, if possible; e.g, '10' - '2' yields 8, because both operands were implicitly converted to [int]s.
[1] Typically, it is the LHS of an operation that determines its data type, causing the RHS to be coerced to a matching type, if necessary.
This should be really simple, but I cannot make it work. I'm new to the PowerShell so my mistake is probably obvious. I'm trying to ask a user for an input using a while loop, and prompting the user to try again if what was entered was not numeric. In bash it would look like this:
while read -p "What is the first number? " first; do
if [[ $first = *[[:digit:]]* ]]; then
break # if $first is numeric, break loop
else
echo "$first is not numeric. Enter a numeric value. "
fi
done
Here's what I have for the PS:
While ($first = (Read-Host "What is the first number?") -as [double]) {
if ($first -eq $null) { Write-Host "Please enter a numeric value." }
else { break }
}
In the example above, I can break the loop fine when a number is entered, but I can't see the Write-Host statement if I type a string.
Looking at the While line:
While ($first = (Read-Host "What is the first number?") -as [double])
This will only enter/continue the loop body when the input is already a double, because it rolls up the cast to double as part of the loop condition. You want to enter the loop body on any input, and only check if it's a double afterwards. At least, that's what the bash code does:
While ($first = (Read-Host "What is the first number?")) {
if ( ($first -as [double]) -eq $null) { Write-Host "Please enter a numeric value." }
else { break }
}
Or you could continue using the cast as part of the condition by negating the whole expression, and thus avoid the need for the awkward break:
While (-not ($first = (Read-Host "What is the first number?") -as [double])) {
Write-Host "Please enter a numeric value."
}
You could use this to keep prompting for a valid number input as you are looking for.
Do {
"Please enter a numeric value." | Out-Host
$first = (Read-Host "What is the first number?") -as [double]
} While($null -eq $first)
I have the following PowerShell script that creates a random string of 15 digits, for use as an Active Directory password.
The trouble is, this works great most of the time, but on some occasions it doesn't use a number or symbol. I just get 15 letters. This is then not usable as an Active Directory password, as it must have at least one number or symbol in it.
$punc = 46..46
$digits = 48..57
$letters = 65..90 + 97..122
$YouShallNotPass = get-random -count 15 `
-input ($punc + $digits + $letters) |
% -begin { $aa = $null } `
-process {$aa += [char]$_} `
-end {$aa}
Write-Host "Password is $YouShallNotPass"
How would I amend the script to always have at least one random number or symbol in it?
Thank you.
You could invoke the Get-Random cmdlet three times, each time with a different input parameter (punc, digit and letters), concat the result strings and shuffle them using another Get-Random invoke:
(Get-Random -Count 15 -InputObject ([char[]]$yourPassword)) -join ''
However, why do you want to reinvent the wheel? Consider using the following GeneratePassword function:
[Reflection.Assembly]::LoadWithPartialName("System.Web")
[System.Web.Security.Membership]::GeneratePassword(15,2)
And to ensure, it contains at least one random number (you already specify the number of symbols):
do {
$pwd = [System.Web.Security.Membership]::GeneratePassword(15,2)
} until ($pwd -match '\d')
As suggested by jisaak, there is no 100% guaranty that the Membership.GeneratePassword Method generates a password that meets the AD complexity requirements.
That's why I reinvented the wheel:
Function Create-String([Int]$Size = 8, [Char[]]$CharSets = "ULNS", [Char[]]$Exclude) {
$Chars = #(); $TokenSet = #()
If (!$TokenSets) {$Global:TokenSets = #{
U = [Char[]]'ABCDEFGHIJKLMNOPQRSTUVWXYZ' #Upper case
L = [Char[]]'abcdefghijklmnopqrstuvwxyz' #Lower case
N = [Char[]]'0123456789' #Numerals
S = [Char[]]'!"#$%&''()*+,-./:;<=>?#[\]^_`{|}~' #Symbols
}}
$CharSets | ForEach {
$Tokens = $TokenSets."$_" | ForEach {If ($Exclude -cNotContains $_) {$_}}
If ($Tokens) {
$TokensSet += $Tokens
If ($_ -cle [Char]"Z") {$Chars += $Tokens | Get-Random} #Character sets defined in upper case are mandatory
}
}
While ($Chars.Count -lt $Size) {$Chars += $TokensSet | Get-Random}
($Chars | Sort-Object {Get-Random}) -Join "" #Mix the (mandatory) characters and output string
}; Set-Alias Create-Password Create-String -Description "Generate a random string (password)"
Usage:
The Size parameter defines the length of the password.
The CharSets parameter defines the complexity where the character U,
L, N and S stands for Uppercase, Lowercase, Numerals and Symbols.
If supplied in lowercase (u, l, n or s) the returned string
might contain any of character in the concerned character set, If
supplied in uppercase (U, L, N or S) the returned string will
contain at least one of the characters in the concerned character
set.
The Exclude parameter lets you exclude specific characters that might e.g.
lead to confusion like an alphanumeric O and a numeric 0 (zero).
Examples:
To create a password with a length of 8 characters that might contain any uppercase characters, lowercase characters and numbers:
Create-Password 8 uln
To create a password with a length of 12 characters that that contains at least one uppercase character, one lowercase character, one number and one symbol and does not contain the characters OLIoli01:
Create-Password 12 ULNS "OLIoli01"
For the latest New-Password version: use:
Install-Script -Name PowerSnippets.New-Password
Command to Generate Random passwords by using existing funciton:
[system.web.security.membership]::GeneratePassword(x,y)
x = Length of the password
y = Complexity
General Error:
Unable to find type [system.web.security.membership]. Make sure that the assembly that contains this type is loaded.
Solution:
Run the below command:
Add-Type -AssemblyName System.web;
Another solution:
function New-Password() {
param(
[int] $Length = 10,
[bool] $Upper = $true,
[bool] $Lower = $true,
[bool] $Numeric = $true,
[string] $Special
)
$upperChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
$lowerChars = "abcdefghijklmnopqrstuvwxyz"
$numericChars = "0123456789"
$all = ""
if ($Upper) { $all = "$all$upperChars" }
if ($Lower) { $all = "$all$lowerChars" }
if ($Numeric) { $all = "$all$numericChars" }
if ($Special -and ($special.Length -gt 0)) { $all = "$all$Special" }
$password = ""
for ($i = 0; $i -lt $Length; $i++) {
Write-Host "password: [$password]"
$password = $password + $all[$(Get-Random -Minimum 0 -Maximum $all.Length)]
}
$valid = $true
if ($Upper -and ($password.IndexOfAny($upperChars.ToCharArray()) -eq -1)) { $valid = $false }
if ($Lower -and ($password.IndexOfAny($lowerChars.ToCharArray()) -eq -1)) { $valid = $false }
if ($Numeric -and ($password.IndexOfAny($numericChars.ToCharArray()) -eq -1)) { $valid = $false }
if ($Special -and $Special.Length -gt 1 -and ($password.IndexOfAny($Special.ToCharArray()) -eq -1)) { $valid = $false }
if (-not $valid) {
$password = New-Password `
-Length $Length `
-Upper $Upper `
-Lower $Lower `
-Numeric $Numeric `
-Special $Special
}
return $password
}
Flexible enough to set length, turn on/of upper, lower, and numeric, and set the list of specials.
My take on generating passwords in PowerShell, based on what I've found here and in the Internets:
#Requires -Version 4.0
[CmdletBinding(PositionalBinding=$false)]
param (
[Parameter(
Mandatory = $false,
HelpMessage = "Minimum password length"
)]
[ValidateRange(1,[int]::MaxValue)]
[int]$MinimumLength = 24,
[Parameter(
Mandatory = $false,
HelpMessage = "Maximum password length"
)]
[ValidateRange(1,[int]::MaxValue)]
[int]$MaximumLength = 42,
[Parameter(
Mandatory = $false,
HelpMessage = "Characters which can be used in the password"
)]
[ValidateNotNullOrEmpty()]
[string]$Characters = '1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM##%*-_+:,.'
)
(1..(Get-Random -Minimum $MinimumLength -Maximum $MaximumLength) `
| %{ `
$Characters.GetEnumerator() | Get-Random `
}) -join ''
I preferred this over using System.Web, not to introduce dependencies, which could change with .Net / .Net Core versions.
My variation also allows random password length (in specified range), is fairly concise (apart from the parameters section, which is quite verbose, to enforce some validations and provide defaults) and allows character repetitions (as opposite to the code in the question, which never repeats the same character).
I understand, that this does not guarantee a digit in the password. This however can be addressed in different ways. E.g. as was suggested, to repeat the generation until the password matches the requirements (contains a digit). My take would be:
Generate a random password.
If it does not contain a digit (or always):
Use a random function to get 1 random digit.
Add it to the random password.
Randomize the order of the result (so the digit is not necessarily always at the end).
Assuming, that the above script would be named "Get-RandomPassword.ps1", it could look like this:
$pass = .\Get-RandomPassword.ps1
$pass += (0..9 | Get-Random)
$pass = (($pass.GetEnumerator() | Get-Random -Count $pass.Length) -join '')
Write-Output $pass
This can be generalized, to enforce using any character category:
$sets = #('abcdefghijklmnopqrstuvwxyz', 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', '0123456789', '()-_=+[{]};:''",<.>/?`~')
$pass = .\Get-RandomPassword.ps1 -Characters ($sets -join '')
foreach ($set in $sets) {
$pass += ($set.GetEnumerator() | Get-Random)
}
$pass = (($pass.GetEnumerator() | Get-Random -Count $pass.Length) -join '')
Write-Output $pass
I wrote a secure password generator function in PowerShell, maybe this will be useful to someone.
Similar to the accepted answer, this script also uses Get-Random (twice), and also regular expression matching to ensure the output is secure.
The difference in this script is that the password length can also be randomised.
(To hard set a password length, just set the MinimumPasswordLength and MaximumPasswordLength values to the the same length.)
It also allows an easy to edit character set, and also has a regex to ensure a decent password has been generated with all of the following characteristics:
(?=.*\d) must contain at least one numerical character
(?=.*[a-z]) must contain at least one lowercase character
(?=.*[A-Z]) must contain at least one uppercase character
(?=.*\W) must contain at least one non-word character
The answer to your question about always including a number in your generated output can be solved by checking the output with a regex match (just use the parts of the regex that you need, based on the explanations above), the example here checks for uppercase, lowercase, and numerical:
$Regex = "(?=.*\d)(?=.*[a-z])(?=.*[A-Z])"
do {
$Password = ([string]($AllowedPasswordCharacters |
Get-Random -Count $PasswordLength) -replace ' ')
} until ($Password -cmatch $Regex)
$Password
Here is the full script:
Function GeneratePassword
{
cls
$MinimumPasswordLength = 12
$MaximumPasswordLength = 16
$PasswordLength = Get-Random -InputObject ($MinimumPasswordLength..$MaximumPasswordLength)
$AllowedPasswordCharacters = [char[]]'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!?##£$%^&'
$Regex = "(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*\W)"
do {
$Password = ([string]($AllowedPasswordCharacters |
Get-Random -Count $PasswordLength) -replace ' ')
} until ($Password -cmatch $Regex)
$Password
}
GeneratePassword
I had the same issue here is the snippet I used to create my alphanumerical password its simple all I have done is used ASCII regex replace to make it nice.
Function Password-Generator ([int]$Length)
{
# Generate passwords just call password-generator(lenght of password)
$Assembly = Add-Type -AssemblyName System.Web
$RandomComplexPassword = [System.Web.Security.Membership]::GeneratePassword($Length,2)
$AlphaNumericalPassword = $RandomComplexPassword -replace '[^\x30-\x39\x41-\x5A\x61-\x7A]+'
Write-Output $AlphaNumericalPassword
}
I've created this. You can choose how many Pwd to create
$howoften = Read-Host "How many would you like to create: "
$i = 0
do{
(-join(1..42 | ForEach {((65..90)+(97..122)+(".") | % {[char]$_})+(0..9)+(".") | Get-Random}))
$i++
} until ($i -match $howoften)
To change the length of the pwd simply edit the "42" in line 4
(-join(1..**42** | ForEach ...