Re: Default PATH setting - reduce to something more sensible?

On 23.01.2025 23:46, Keith Thompson wrote:

Kaz Kylheku <643-408-1753@kylheku.com> writes:
[...]

The obvious situation is double quotes. Inside double quotes, parameter
expansion happens, but not tilde expansion (not to mention pathname
expansion (globbing) and perhaps some other things).
>
So this won't work:
>
 PATH="$PATH:~/bin"
>

Sorry I don't have details, but it is true nonetheless.

>
There they are.

[...]
 
In fact it probably will *partially* work.  As I mentioned elsethread,
bash expands a leading ~ (or even ~username) in an element of $PATH when
executing a command.

Interpretation of any _leading_ '~' is the documented behavior for
tilde expansion.

 
But if you run a program from the command line that invokes another
program (say, a C program that calls system()), it won't treat that
element of $PATH the same way.

I think the point is that the _shell_ expands the expression.

Whether you do PATH="~" or PATH='~' or PATH=\~ , in all cases you have
defined a variable value that contains '~', a tilde. Not an expanded
tilde-expression. So if you 'exec' a command that PATH variable (with
the literal tilde) will get passed to the executable environment (and
no shell interpretation takes place).

Use PATH=~ instead if you want it expanded.

 
For this and other reasons, though you *can* have a literal ~ in $PATH
in bash, it's best to avoid it and use $HOME instead.

Or use it correctly, unquoted and unescaped.

Janis

A literal '$HOME'
won't work at all, but that's less likely to be a problem if your at all
aware of how double quotes work in the shell.
 
I suggest that bash's undocumented behavior is less than helpful.
I'll probably submit a bug report.