[Help-bash] Is there a way to access a global variable once a local variable with the same name is declared?

[Peng Yu]

Hi,

Is there a way to access a global variable once a local variable with
the same name is declared? Thanks.

$ cat main.sh
#!/usr/bin/env bash
# vim: set noexpandtab tabstop=2:

set -v
function f {
local x
declare -p x
# I like to access the global x as well here.
}
x=1
f
declare -p x

$ ./main.sh
function f {
local x
declare -p x
}
x=1
f
declare -- x
declare -p x
declare -- x="1"

[Grisha Levit]

Post by Peng Yu
Is there a way to access a global variable once a local variable with
the same name is declared? Thanks.

A local circular nameref will resolve to the global variable of the same
name.

So you can make a function to retrieve a global variable's value, like:

$ g() { declare -n $1=$1; printf %s "${!1}"; } 2>/dev/null
$ x=1; f() { local x=2; g x; }; f
1

You will need something a bit fancier for arrays, depending on how exactly
you want to access their values.

[Peng Yu]

Post by Grisha Levit
$ g() { declare -n $1=$1; printf %s "${!1}"; } 2>/dev/null
$ x=1; f() { local x=2; g x; }; f
1

I don't see the "1" printed at the end. Anything wrong?

--
Regards,
Peng

[Grisha Levit]

This is actually only in bash 5.

Post by Peng Yu

Post by Grisha Levit
$ g() { declare -n $1=$1; printf %s "${!1}"; } 2>/dev/null
$ x=1; f() { local x=2; g x; }; f
1

I don't see the "1" printed at the end. Anything wrong?
--
Regards,
Peng

[Peng Yu]

Where is 5? I only see 4.4.

https://github.com/bminor/bash

Post by Grisha Levit
This is actually only in bash 5.

Post by Peng Yu

Post by Grisha Levit
$ g() { declare -n $1=$1; printf %s "${!1}"; } 2>/dev/null
$ x=1; f() { local x=2; g x; }; f
1

I don't see the "1" printed at the end. Anything wrong?
--
Regards,
Peng

[Grisha Levit]

That's some unofficial mirror. Official repo is at
https://git.savannah.gnu.org/cgit/bash.git, check the devel branch.

Post by Peng Yu
Where is 5? I only see 4.4.
https://github.com/bminor/bash

Post by Grisha Levit
This is actually only in bash 5.

Post by Peng Yu

Post by Grisha Levit
$ g() { declare -n $1=$1; printf %s "${!1}"; } 2>/dev/null
$ x=1; f() { local x=2; g x; }; f
1

I don't see the "1" printed at the end. Anything wrong?
--
Regards,
Peng

--
Regards,
Peng

[Chet Ramey]

Post by Grisha Levit
That's some unofficial mirror. Official repo is at
https://git.savannah.gnu.org/cgit/bash.git, check the devel branch.

For alpha and beta releases, use the bash-5.0-testing branch. The devel
branch is for ongoing development.