Compare exec stdout with some text using shelljs

Question

When running sh.exec('whoami') I am trying to compare the stdout but it doesn't work.

What I want to do is that after running the whoami command if the results turns to be an specific user then I would like to trigger an action.

When running,

sh.exec('whoami', (code, output) => {
  sh.echo(output == 'myusername'); // False
  console.log(output == 'myusername'); // False
});

The condition output == 'myusername' evaluates to false even though I am completely sure it is true since I've copied the username and place it as the compared string.

The expected result would be that the condition evaluates to true.

try to log `output`. Then it might have some spaces. Also try to compare them `char` by `char` to see if they are using same unicode — Void Spirit, Apr 26 '19 at 17:42
`whoami` outputs a trailing linefeed. Maybe getting `'myusername\n'` as output? — that other guy, Apr 26 '19 at 17:44
Thanks a bunch @AntihypeBird! I did as you said and noticed stdout puts an extra \n at the end. — gmotzespina, Apr 26 '19 at 17:51

score 0 · Answer 1 · answered Apr 26 '19 at 17:47

0

Doing,

 console.log(sh.exec('whoami'));

You get the following output,

{ [String: 'username\n']
  stdout: 'username\n',
  stderr: '',
  code: 0,
  cat: [Function: bound ],
  exec: [Function: bound ],
  grep: [Function: bound ],
  head: [Function: bound ],
  sed: [Function: bound ],
  sort: [Function: bound ],
  tail: [Function: bound ],
  to: [Function: bound ],
  toEnd: [Function: bound ],
  uniq: [Function: bound ] 
}

The problem was just a new line. stdout comes with a \n at the end.

answered Apr 26 '19 at 17:47

gmotzespina

143
7

In the body of your callback function passed to `exec` consider utilizing the [`trim()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/Trim) method to remove the `\n` before checking for equality. For Instance: `sh.exec('whoami', (code, output) => { sh.echo(output.trim() === 'myusername'); });` – RobC May 02 '19 at 08:49

Compare exec stdout with some text using shelljs

1 Answers1