Question

I have a shell script which gets executed. In the script I have:

if [[ $variable == *something* ]]; then
   do something
fi

My issue here is that running the script returns “[[ not found”.

From reading other answers, it looks like not all shells recognize double brackets, however, I am not sure what the solution is, what is the equivalent of that code?

Answer 1

It sounds like your shell is POSIX sh, which does not have the [[ builtin. Possible solutions include translating it to an expression that works for sh or changing the shebang line to be #!/bin/bash. Changing the shebang is generally the best solution.

You may have a POSIX sh if you’re on Ubuntu, they use dash.