Bash - check if argument is string-CodePudding

I am attempting to check if an argument is an array with the following code:

if [[ $(declare -p $1) ]] != *-a*;

Here $1 is a string with the value "123". I get the following error message from bash:

`arrays.bash: line 23: declare: 123: not found

This code works if I pass an array as an argument but not a string. I want to verify that the argument is either an array or an associative array. I have no concern with the contents at this point, I only want the type. Any ideas on how to do this?

CodePudding user response：

After all, why worry about the types, if you are relying on it perhaps your approach is wrong or you may need a strong-typed language

% v=1
% declare -p v
declare -- v="1"
% echo $v
1
% echo ${v[@]}
1
% v[1]=2
% declare -p v
declare -a v=([0]="1" [1]="2")
% echo ${v[@]}
1 2

CodePudding user response：

To check if an argument is an array or associative you can do something like this:

if [[ "$(declare -p "${1}")" =~ declare\ \-a ]] ; then
    echo "TRUE"
fi

However, in bash variables are untyped. For this reason it would probably be best to use a different langauge in this scenario.