7

I am seeing strange behavior when trying to store the output of an SSH check to see if I have SSH access to an account. I tried the following:

ssh [email protected] > temp.txt

and I expect a string message telling me if permission was denied or not to be saved to temp.txt. But the output goes straight to the terminal and isn't saved to file. But, if I do

ls -l > temp.txt

that output is saved to file. What could be causing this difference in behavior? I'm ultimately going to be saving the output to a variable but see similar behavior for that case as well. I'm on Ubuntu 16.04 bash version 4.3.48(1).

Improve this question
2
  • 1
    Since "permission denied" is typically considered an error, is the output being routed to stderr instead of stdout? If so, you need to use 2> temp.txt or > temp.txt 2>&1. Commented Mar 7, 2018 at 21:25
  • @0x5453 I think you're right, that's what I needed to do, and in fact that's in the link I posted I just didn't understand what that syntax meant. Also on a different machine it was working, so it seemed system dependent. Can you write as answer? I'll mark accepted. Commented Mar 7, 2018 at 21:29

2 Answers 2

Reset to default
5

Since "permission denied" is typically considered an error, is the output being routed to stderr instead of stdout? If so, you need to use 2> temp.txt or > temp.txt 2>&1.

More information:

On many systems, program output is broken up into multiple streams, most commonly stdout (standard output) and stderr (standard error). When you use >, that only redirects stdout, but 2> can be used to redirect stderr. (This is useful if you want normal output and errors to go to two different files.)

The syntax 2>&1 means "take all output on stderr and redirect it to stdout", so your file would contain output from both streams.

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

Comments

2

Try this:

ssh [email protected] > temp.txt 2>&1

Basically what this does it tells linux to redirect stderr (2) to stdout (&1), and then redirect stdout to your file "temp.txt"

Improve this answer

Comments

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.