Re: Env var feature request

[Greg Wooledge]

On Tue, Jul 09, 2024 at 20:14:27 +0000, Erik Keever wrote:
> A --debug-envvars flag which will, when passed to bash, catch every time an 
> environment variable is set and print the file/line that is setting it. To 
> restrict it, "--debug-envvars FOO,BAR" to catch only instances of FOO or BAR 
> being set.

It's not *exactly* what you're asking for, but you can get most of
this by invoking bash in xtrace mode with PS4 set to a custom value:

    PS4='+ $BASH_SOURCE:$FUNCNAME:$LINENO:' bash -ilxc : 2>&1 | grep WHATEVER

That will show you where WHATEVER is being set during an interactive
shell login, for example.  Omit the "l" flag if you want to debug a
non-login shell instead.

Note that if bash is being run as UID 0, it will ignore PS4 coming from
the environment, for security reasons.  So, this only works as a non-root
user.