Question

So I have this block of code. Basically, I’m taking file $i, checking if it’s got content or not, checking if I can read it, if I can open it, grab the first line and see if it’s a bash file. When I run this every time on a non-empty file, it was registers as true and echo’s bash.

            ## File is empty or not
            if [[ -s $i ]]
            then
                ## Can we read the file 
                if [[ -r $i ]]
                then
                    ## File has content
                    if [[ $(head -n 1 $i) = "#! /bin/bash" ]]
                    then
                        echo -n " bash"
                    fi
                fi
            else
                ## file does not have content
                echo -n " empty"
            fi

This is what does the check of if it’s bash:

if [[ $(head -n 1 $i) = "#! /bin/bash" ]]

Answer 1

Replace [[ with [ and enclose $(head -n 1 $i) in quotes.

[[ is itself an operator that tests its contents.