Would like to check user input for letters within a loop Post: 303027049

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Top Forums Shell Programming and Scripting Would like to check user input for letters within a loop Post 303027049 by jvezinat on Friday 7th of December 2018 02:02:53 PM

12-07-2018

Registered User

Would like to check user input for letters within a loop

Hi All,

Code:

#!/bin/bash

#Just trying to check if letters are in the user input. Any tips?
# I have tried regexp and using 0-9 etc, i cannot get this to work either in just an if statement or while in a loop.

echo "Please pick a number"
read num
if [ -z $num ]; then
	echo "Please enter a number"
	read num
elif [[ $num != [[:digit:]] ]]; then
	echo "That is not a number, try again!"
	read num
# I have tried [0-9] etc and does not work.

elif	[[ $num = [[:digit:]] ]]; then
	echo $num
	echo "This is a number"
fi

# i understand this would need to be in a loop to continuously check until a number is chosen
# as of now it is always returning "That is not a number, try again!"
# I have an entire guessing working until i put anything that tries to verify if user input has letters.  If letters are present, i will be prompting for them to enter numbers within the loop.

THANKS!

--- Post updated at 07:02 PM ---

Got it to work but it only checks the first digit of the $number variable
Does anyone know how to have the have the script check if there are any letters throughout the $number variable/

Code:

#!/bin/bash
echo "Please pick number"
read number

if [ -z $number ]; then
echo "Please input a number"
read number

elif [[ ! $number == [0-9] ]]; then
echo "Not a number, Try again!"
read number

elif
[[ $number == [0-9]; then
echo $number
echo "That is a number!"
fi

# I can only check the first digit, how can i check the entire $number variable for any letters?

Thanks!

Last edited by Scrutinizer; 12-07-2018 at 03:16 PM.. Reason: code tags

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LEARN ABOUT PHP

array_rand

ARRAY_RAND(3)								 1							     ARRAY_RAND(3)

array_rand - Pick one or more random entries out of an array

SYNOPSIS

       mixed array_rand (array	$array, [int  $num = 1])

DESCRIPTION

	Picks one or more random entries out of an array, and returns the key (or keys) of the random entries.

PARAMETERS

	      o $array
		- The input array.

	      o $num
		- Specifies how many entries should be picked.

RETURN VALUES

	When  picking  only  one  entry,  array_rand(3)  returns the key for a random entry. Otherwise, an array of keys for the random entries is
       returned. This is done so that random keys can be picked from the array as well as random values. Trying to pick more elements  than  there
       are in the array will result in an E_WARNING level error, and NULL will be returned.

CHANGELOG

       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       |5.2.10	|						    |
       |	|						    |
       |	|  The	resulting  array of keys is no longer shuf- |
       |	| fled. 					    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES

       Example #1

	      array_rand(3) example

	      <?php
	      $input = array("Neo", "Morpheus", "Trinity", "Cypher", "Tank");
	      $rand_keys = array_rand($input, 2);
	      echo $input[$rand_keys[0]] . "
";
	      echo $input[$rand_keys[1]] . "
";
	      ?>

SEE ALSO

       shuffle(3).

PHP Documentation Group 													     ARRAY_RAND(3)