On 9/21/18 7:49 AM, [email protected] wrote:
> According to the manual:
>
> (I) Typing the suspend character (typically ^Z, Control-Z)
> while a process is running causes that process to be
> stopped and returns control to bash.
>
> (II) An OR list has the form
>
> command1 || command2
>
> command2 is executed if and only if command1
> returns a non-zero exit status. The return status of
> AND and OR lists is the exit status of the last
> command executed in the list.
>
> In the following example:
>
> esoriano@omac:~$ sleep 10 || echo hey
> ^Z
> [5]+ Stopped sleep 10
> hey
> esoriano@omac:~$
>
> there are two different issues:
>
> (I) echo is executed when sleep is suspended, i.e., command2 is
> executed before command1 exits.
This is true, and it's the difference between a process, which is the
object you suspend, and a shell command. When you suspend the sleep,
it returns a status: 128+SIGTSTP. Since this is non-zero, the second
part of the AND-OR list gets executed.
The idiomatic way to do what you want is to get the command you want
to run as a unit into a construct like (...) -- if you want to run it
in the foreground -- so you have a single process that you can suspend.
This has come up many times, in the context of compound commands like
loops and command sequences.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU [email protected] http://tiswww.cwru.edu/~chet/
