Error: =: command not found (Bash Script)

Question

I found a nifty little shell script that I wanted to use from this website here. I have followed everything step-by-step, but receive the following error when running this on my CentOS box.

./deploy: line 3: =: command not found

Line 3 only contains...

$ERRORSTRING = "Error. Please make sure you've indicated correct parameters"

I've tried toying around with a bit, but don't understand why it won't accept the "=" character. Is there something wrong with the script, or is it merely something different in the way that my server processes the script?

Thanks!

Answer 1

Gah, that script is full of bad scripting practices (in addition to the outright error you're running into). Here's the outright error:

$ERRORSTRING = "Error. Please make sure you've indicated correct parameters"

As devnull pointed out, this should be:

ERRORSTRING="Error. Please make sure you've indicated correct parameters"

A couple of lines down (and again near the end), we have:

echo $ERRORSTRING;

...which works, but contains two bad ideas: a variable reference without double-quotes around it (which will sometimes be parsed in unexpected ways), and a semicolon at the end of the line (which is a sign that someone is trying to write C or Java or something in a shell script). Use this instead:

echo "$ERRORSTRING"

The next line is:

elif [ $1 == "live" ]

...which might work, depending on whether the value of $1 has spaces, or is defined-but-blank, or anything like that (again, use double-quotes to prevent misparsing!). Also, the == comparison operator is nonstandard -- it'll work, because bash supports it in its [ ... ] builtin syntax, but if you're counting on having bash extensions available, why not use the much cleaner [[ ... ]] replacement? Any of these would be a better replacement for that line:

elif [ "$1" = "live" ]
elif [[ $1 == "live" ]]
elif [[ "$1" == "live" ]]

Personally, I prefer the last. The double-quotes aren't needed in this particular case, but IMO it's safest to just double-quote all variable references unless there's a specific reason not to. A bit further down, there's a elif [ $2 == "go" ] that the same comments apply to.

BTW, there's a good sanity-checking tool for shell scripts at www.shellcheck.net. It's not quite as picky as I am (e.g. it doesn't flag semicolons at the ends of lines), but it pointed out all of the actual errors in this script...