Re: [Help-bash] echo and environment variables

[Nick Chambers]

On Thu, Oct 5, 2017 at 12:24 PM Christof Warlich <address@hidden>
wrote:

> Hi,
>
> I'm a bit surprised: Can anyone tell why
>
> $ xxx=hiho echo $xxx # xxx is only set for the current command
>
> prints an empty line, while
>
> $ xxx=hiho; echo $xxx; unset xxx # please note the semicolon!
>
> prints
>
> hiho
>
> as expected?
>
> Furthermore, note that these few lines of C code:
>
> #include <stdio.h>
> #include <stdlib.h>
> int main () {
>    char *xxx = getenv ("xxx");
>    if(xxx != NULL) printf("%s\n", xxx);
>    return 0;
> }
>
> _do_ print
>
> hiho
>
> when called either way, i.e like this.:
>
> $ xxx=hiho ./a.out
> hiho
>
> and like this:
>
> xxx=hiho; ./a.out; unset xxx
> hiho
>
> Thanks for any ideas,
>
> Chris


http://mywiki.wooledge.org/BashFAQ?action=show&redirect=BashFaq#BashFAQ.2F104.Why_doesn.27t_foo.3Dbar_echo_.22.24foo.22_print_bar.3F

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