Validate variables from another bash script

Question

I have a script that asks for the user to enter a username and password. I want to compare the input to the username and password variables stored in a passwords.txt file. I tried using source but it does not give me access to the variables. Here are my parts of my files below:

passwords.txt

 #!/bin/bash 
 username="username"
 password="password"

script.bash

 #!/bin/bash
 echo "Enter username"
 read -r user
 echo "Enter password"
 read -r pass
 source passwords.txt

 if("$user" == "$username" && "$pass" == "$password") then 
      echo "You have successfully logged in"
 else 
      echo "You entered the wrong credentials"
 fi

If you can, please help me figure out how to compare the two variables in different files.

The syntax for the if statement is incorrect, is this the actual code you are using? — cdarke
– cdarke, Commented Apr 24, 2016 at 21:04

mklement0 · Accepted Answer · 2016-04-24 21:33:48Z

5

The problem is not with sourcing, but with the syntax of your if statement.

That said, storing plain-text passwords in files and prompting users for passwords typed visibly are both practices to be avoided for security reasons.

With that out of the way, here's the Bash code that shows the proper form of the conditional:

 echo "Enter username"
 read -r user
 echo "Enter password"
 read -r pass
 source passwords.txt

 if [[ "$user" == "$username" && "$pass" == "$password" ]]; then 
      echo "You have successfully logged in"
 else 
      echo "You entered the wrong credentials"
 fi

Generally, consider using shellcheck.net to find syntax problems in your shell code.

In your specific case, as you point out in a comment, shellcheck.net wouldn't have helped, however:

(...) as a conditional passed to if is valid in principle, for executing a command whose exit code to test (although enclosing in (...) is typically not needed for that, because all that does is run the command in a subshell).

By contrast, you were looking to evaluate an expression, which is what syntax [[ ... ]] is for - see the Bash manual online or section CONDITIONAL EXPRESSIONS in man bash.

edited Apr 24, 2016 at 21:33

answered Apr 24, 2016 at 21:07

mklement0

452k68 gold badges728 silver badges987 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

emery Over a year ago

Well answered, mklement0. Ashley, if this is a professional program, you'll want to run through a tutorial or blog post on how to handle secure passwords in bash.

Ashley Over a year ago

Thank you @mklemento0 this works now! I actually did run the code through shellcheck.net before I used source and it did not give me any errors. And I am aware that this is not best practice but this is for an assignment that I am completing and this is part of the problem that was requested.

mklement0 Over a year ago

@Ashley Glad to hear it; re use of shellcheck.net: understood - please see my update.

Ashley Over a year ago

Thanks again @mklement0 I see the difference in the two if statements now

Collectives™ on Stack Overflow

Validate variables from another bash script

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related