Associative arrays: error "declare: -A: invalid option"

I've written a script that uses associative arrays in bash (v 4).

It works fine on my local machine which is using 4.1.5(1)-release.

On the production machine, using 4.1.0(1)-release the following line, which declares the assoc array, fails:

declare -A uniqjars

with the message:

/script.sh: line 11: declare: -A: invalid option
declare: usage: declare [-afFirtx] [-p] [name[=value] ...]

I was under the impression this was a general bash 4 feature?

In the man for bash on the production machine it discusses using -A so I assume it should work.

> Associative arrays are created using > declare -A name.

I can confirm the script is using the right version of bash by printing out the value of echo 'bash -version.

What could I be doing wrong?

Make sure the version of bash being invoked as interpreter at the top of your shell script (#!/bin/bash or whatever) is also version 4. If you're doing:

bash --version

and it's giving you v4, do a which bash to check it's location.

The following seems to be a typical scenario on macOS after installing a newer Bash with Homebrew:

• /bin/bash is the old Bash, 3.2
• /usr/local/bin/bash is the new Bash that knows about associative arrays (4.0 or newer)
• type bash points to /usr/local/bin/bash and bash --version is the new one (because it resolves to /usr/local/bin/bash --version)

However, scripts with a #!/bin/bash shebang line that are run with ./script will use the old Bash (the scenario in the question). Solutions are:

• Call the script with bash script: the new Bash will be used. Disadvantage: you always have to call it like that.
• Change the shebang line to #!/usr/local/bin/bash. Disadvantage: on many systems, there is no Bash in /usr/local/bin and your script isn't portable any longer.
• Change the shebang line to #!/usr/bin/env bash. This will use the first bash in your PATH, which should be the new one. This is pretty portable; the only downside is that you don't know exactly which Bash will be executed.

See also these Q&A:

• https://stackoverflow.com/q/16365130/3266847
• https://stackoverflow.com/q/21612980/3266847
• Why is it better to use “#!/usr/bin/env NAME” instead of “#!/path/to/NAME” as my shebang? on Unix & Linux

Here is a Workaround, if you want to use chars as array index with bash v3:

array=(
	'hello::world.'
	'nice::to meet you'
)

for index in "${array[@]}" ; do
	KEY="${index%%::*}"
	VALUE="${index##*::}"
	echo "$KEY - $VALUE"
done

Output:

hello - world.
nice - to meet you

Here is how to get the updated bash version on OS X, you should install brew and then bash.

$ /bin/bash --version    
GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin14)
    
$ brew install bash    
... install

$ /usr/local/bin/bash --version    
GNU bash, version 4.3.46(1)-release (x86_64-apple-darwin14.5.0)

1. Check the current shell you are using with this cmd:

    echo $SHELL
   

E.g. it could say /bin/bash

2. Run --version on that $SHELL:

    /bin/bash --version
   

It may output something like GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin16)

If it is before version 4, you'll have to upgrade.

3. Check if you already have a bash shell with version 4. Try running:

    bash --version
   

If so, you just need to change your default shell to that shell.

You can use these cmds to do so:

    sudo bash -c 'echo /usr/local/bin/bash >> /etc/shells'
    sudo chsh -s /usr/local/bin/bash

The first adds the shell to the allowed shells. The second actually changes your default shell.

meigrafd's answer solved my problem, so if using an incorrect shebang or still on bash version 3 the following allowed me to return a value based on it's associated key:

array=(
    'hello::world.'
    'nice::to meet you'
)

for index in "${array[@]}" ; do
  KEY="${index%%::*}"
  VALUE="${index##*::}"
  if [ "$KEY" == "nice" ]; then
    echo "$VALUE"
    break
  fi
done

This will return the value "to meet you".

Old BASH version didn't support declare -A syntax of declaring arrays. I suggest using either of these 2 forms to declare arrays in bash to make it compatible with older bash version of your production system:

arr=( '10' '20' '30' )
echo ${arr[@]}

or

arr[0]=10
arr[1]=20
arr[2]=30
echo ${arr[@]}

Nothing above helped me, so I opened /etc/shells and changed the line

• /bin/bash to /usr/local/bin/bash, and then reloaded it with source /etc/shells and now I can enjoy new possibilities of v4 of bash

Per the command:

help declare
declare: declare [-aAfFgilnrtux] [-p] [name[=value] ...]
  Set variable values and attributes.

Declare variables and give them attributes.  If no NAMEs are given,
display the attributes and values of all variables.
Options which are set attributes:
  -a        to make NAMEs indexed arrays (if supported)
  -A        to make NAMEs associative arrays (if supported)

Notice lowercase "-a" and uppercase "-A" are "(if supported)". Also if you look at the posted error message for declare usage:

/script.sh: line 11: declare: -A: invalid option
declare: usage: declare [-afFirtx] [-p] [name[=value] ...]

The given options are "[-afFirtx]" showing to use a lowercase "-a" but no uppercase "-A". Compare that to the usage string from the help command. It looks as if it's just not supported on the given machine.

Try using a different shebang. On my Mac:

$ which bash
/usr/local/bin/bash

So, this script runs fine, producing "Hello World":

#!/usr/local/bin/bash
declare -A assoc
assoc[hello]="Hello World"
echo ${assoc[hello]}