Bash 4 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.

4.1.5(1)-release

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

4.1.0(1)-release

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.

-A

Associative arrays are created using
declare -A name.

declare -A name

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

echo 'bash -version

What could I be doing wrong?

10 Answers
10

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:

#!/bin/bash

bash --version


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

which bash

which bash

/bin/bash

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


::

string='hello::world' && LEFT="${string%%::*}" && RIGHT="${string##*::}" && echo $LEFT "<>" $RIGHT

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

/bin/bash

/usr/local/bin/bash

type bash

/usr/local/bin/bash

bash --version

/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:

#!/bin/bash

./script

bash script

#!/usr/local/bin/bash

/usr/local/bin

#!/usr/bin/env bash

bash

PATH

See also these Q&A:

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

bash

brew

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)


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".

Check the current shell you are using with this cmd:

echo $SHELL


E.g. it could say /bin/bash

/bin/bash

Run --version on that $SHELL:

--version

$SHELL

/bin/bash --version


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

GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin16)

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

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.

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:

declare -A

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

/bin/bash

/usr/local/bin/bash

source /etc/shells

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]}


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.