CODEWITHSUNDEEP
bashshellscripting
Kyu96
Kyu96

Reputation: 1359

Bash substring comparison doesn't work for command expression

I am trying to compare a substring in bash (How to check if a string contains a substring in Bash). Normally I can do this like so:

if [[ "sdfdsfOpenSSHdsfsdf" == *"OpenSSH"* ]]; then echo "substring found"; fi

However, when using an interactive command it doesn't work:

if [[ $(ssh -V) == *"OpenSSH"* ]]; then echo "substring found"; fi

The output of ssh -V is OpenSSH_8.4p1, OpenSSL 1.1.1h 22 Sep 2020, so I would expect the substring to be matched. What am I missing?

Upvotes: 1

Views: 151

Answers (1)

Chris Maes
Chris Maes

Reputation: 37782

the output of ssh -V goes to stderr, you need to redirect to stdout in order to capture it:

ssh -V 2>&1

so the following works:

if [[ $(ssh -V 2>&1) == *"OpenSSH"* ]]; then echo "substring found"; fi

Upvotes: 2

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