String comparsion compare *

Shell Programming and Scripting
1

Dear all

Would anyone tell me how to prevent user from input non asterisk(i.e. *) character via keyboard?

#!/bin/ksh
targetHour=-1
while [[ ($targetHour != "*") && (($targetHour -lt 0)||($targetHour -gt 23)) ]]
do
  echo "Please input target hour":
  read targetHour
done

When I execute the above coding, and then input a "j", it return the following message:

The specified number is not valid for this command.

Thank you very much

2

try adding a line after read line:

echo "$targetHour" | grep -q "^[0-9]+$" || { echo "Invalid entry." ; targetHour=-1 ; }
3

My requirement is only accept user input 0 ~ 23 and * ( not wildcard, asterisk only ).
Would you tell me how to change the code for archiving my goal?

4

Try

targetHour=-1
while [[ $targetHour != "*"  && ( $targetHour -lt 0 || $targetHour -gt 23 || $(echo $targetHour | grep "[a-zA-Z]" -c) != 0 ) ]]
do
  echo "Please input target hour"
  read targetHour
done