How to list bash variable attributes

Question

I'm wondering if there's some command that takes in a variable as an argument, and echoes all of its attributes (integer, array, readonly, etc)

Your "side question" should be asked separately. Putting more than one distinct topic in a question makes it hard to judge which answer is most correct, and introduces corner cases that make site rules (around voting, duplicate management, &c) hard to handle; that's part of why "Too Broad" is a close reason. — Charles Duffy
– Charles Duffy, Commented Oct 3, 2017 at 23:16
(also, filesystem utilities -- particularly including those such as lsattr and stat, or extended versions of find capable of metadata lookup -- aren't part of bash, but are provided by your operating system, so they'd need to be asked with a different set of tags). — Charles Duffy
– Charles Duffy, Commented Oct 3, 2017 at 23:20

randomir · Accepted Answer · 2017-10-03 23:29:40Z

3

I think

$ declare -p var

is what you are looking for:

From help declare:

declare: declare [-aAfFgilnrtux] [-p] [name[=value] ...]
...
-p  display the attributes and value of each NAME

answered Oct 3, 2017 at 23:13

randomir

18.8k1 gold badge46 silver badges60 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

kevin_o · Accepted Answer · 2023-11-14 05:41:40Z

2

Use ${variable@a}. For example:

$ declare -ai X=(1 2 3)
$ echo ${X@a}
ai

Thanks to user "F. Hauri - Give Up GitHub"; I found that notation in their answer to this unrelated question: Unset readonly variable in bash

Here is how to get the flags for variable if you have its name in another variable.

$ S="X"
$ echo ${!S@a}
ai

answered Nov 13, 2023 at 19:38

kevin_o

1017 bronze badges