how to combine two variables in bash-CodePudding

i have variables from x0 to x9 and i created a random number randomnum=$((RANDOM % 10)) now i want to put them as:-

#! /bin/bash

x0="1"
x1="1"
x2="1"
x3="1"
x4="1"
x5="0"
x6="0"
x7="0"
x8="0"
x9="0"

player1=1

if [[ $x$randomnum == $player1 ]]; then     
        echo "it end!"
    fi

here i want to combine $x and $randomnumber. how would i do that?

CodePudding user response：

You have a couple of choices.

Do to exactly what you want, you can use the eval statement to take the result of an expression and execute it as a shell command. For example:

eval selected=\$x$randomnum
if [[ $selected == $player ]]; then
   ...
fi

The expression passed to the eval statement becomes selected=$x1, which we then evalute, setting selected to the value of $x1.

But a better structure for this would be to use an array variable instead of a series of named variables, something like:

randomnum=$(( RANDOM % 10 ))
x=( 1 1 1 1 1 0 0 0 0 0 )
player1 = 1

if [[ ${x[$randomnum]} == $player1 ]]; then
    ...
fi

CodePudding user response：

You need to do this :-

#!/bin/bash

a='1'
b=5
c="${a}${b}"
echo $c

d=15

if [[ $c == $d ]]; then
        echo "it end!"
    fi