Hi,
to...@tuxteam.de wrote:
> Why {PS1:+x} rather than {PS1:-}?
It seemed to be the nearest suitable variation which was similar to the
proposal
[ ${var+x} ]
in
https://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash
where one can see a nice table of ${VARIABLE...} tricks:
parameter expansion VARIABLE set VARIABLE empty VARIABLE unset
...
>From the hint that it is defined by POSIX i got to the table at
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
under "2.6.2 Parameter Expansion".
As stated at other occasions, my shell mindset is still from the late 1980s
when the choice was Bourne shell or C shell. When newer skills are needed,
i search the web or look into my own existing scripts.
Have a nice day :)
Thomas
