Bash script eval with aws command producing "command not found"-CodePudding

I have a short bash script to take in an int from a user to identify to select a certain eks cluster.

When I use eval $(aws eks --region us-east-1 update-kubeconfig --name eventplatform$input)

I get the error: Updated: command not found

This is resolved if I simply change the command to just aws eks --region us-east-1 update-kubeconfig --name eventplatform$input

Why is the eval command not working for this?

#!/usr/bin/env bash -e

read -p "Which cluster are you trying to access? (int >= 0): " input

while [[ -n ${input//[0-9]/} ]]
do
    read -p "Which cluster are you trying to access? (int >= 0): " input
done

eval $(aws eks --region us-east-1 update-kubeconfig --name eventplatform$input)

CodePudding user response：

The eval command isn't supposed to work for this (whatever you expect "work" to mean in this context).

eval runs data as code. Only programs that write well-formed shell commands or scripts to their stdout as data should have that data evaled.

CodePudding user response：

Simple. eval argument should be a string or something that exists to run, not output of other comments

#!/bin/bash

eval "ls" # okay 
# file1.txt
# file2.txt

eval $(ls); # error
# bash: file1.txt: command not found

See help eval

eval: eval [arg ...] Execute arguments as a shell command.
Combine ARGs into a single string, use the result as input to the shell,
and execute the resulting commands.