Re: How to print the actual command for BASH_COMMAND in trap?

[Koichi Murase]

2021年6月13日(日) 19:09 Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>:
>
> also maybe check the 'return' trap
>
> On Sun, Jun 13, 2021, 12:08 Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com> wrote:
>>
>> you can, by setting myvar=$BASH_COMMAND in PS0

I doubt you understand the discussion. 1) PS0 is used in interactive
sessions, but we are talking about non-interactive shell scripts. 2)
PS0 is not evaluated for trap handlers. 3) How we can set the value of
variables inside PS0? One cannot directly specify in PS0 the commands
that will be executed in the main shell. One might do
PS0='$(myvar=$BASH_COMMAND)', but one cannot see the value in the main
shell because that happens in the subshell. One may instead do
PS0='$(echo "$PROMPT_COMMAND" >tmp)' and then read the temporary file
in the main shell. 4) How do you use `return' trap to obtain the
current command in trap handlers? Could you show the code?

--
Koichi