Re: [netrexx-pipelines] Strangeness when filtering linux stty output

[Rony G. F. <Ron...@wu...>]

On 31.07.2023 16:27, Marc Remes wrote:
> pipe 'command stty --all|console also runs fine.. Its output is empty because it is not connected 
> to a real/pseudo terminal, as echo dog |tty reports.
>
> Indeed, we're not doing bash redirection, it is now java that is doing the redirection.
> The command stage starts the stty process by r.exec and connects to its stdin.
> For the stty process there's no difference whether the redirection is done by bash or java, in 
> both cases its stdin is not a terminal. And thus stty has no effect.

According to the JavaDocs for Process 
<https://docs.oracle.com/javase/8/docs/api/java/lang/Process.html> "... By default, the created 
subprocess does not have its own terminal or console. ..." so this may be an explanation that stty 
would not find it and what Marc tries to point out. Not sure about ProcessBuilder 
<https://docs.oracle.com/javase/8/docs/api/java/lang/ProcessBuilder.html> can be used instead and 
making a difference?

Maybe doing something like "stty -F `tty` --all" would work and if not supplying explicitly the 
device path, if known?

---

In ooRexx it works as expected, i.e.

    cmd="stty --all"
    cmd

    -- or redirecting
    arr=.array~new
    address system cmd with output using (arr)
    say 'arr~items:' arr~items
    say arr

---rony


>
> On 7/31/23 16:00, J Leslie Turriff wrote:
>> On 2023-07-31 06:20:50 Marc Remes wrote:
>>> On 7/31/23 13:03, Rony G. Flatscher wrote:
>>>> According to "https://linux.die.net/man/1/stty" "stty --all" would print
>>>> all settings (to stdout I assume).
>>>
>>> True :
>>>
>>> $ stty --all
>>> speed 38400 baud; rows 30; columns 99; line = 0;
>>> intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; eol2
>>> = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R;
>>> werase = ^W; lnext = ^V; discard = ^O; min = 1; time = 0;
>>> -parenb -parodd -cmspar cs8 -hupcl -cstopb cread -clocal -crtscts
>>> -ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon
>>> -ixoff -iuclc -ixany -imaxbel iutf8
>>> opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0
>>> ff0 isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop
>>> -echoprt echoctl echoke -flusho -extproc
>>> $ echo dog | stty
>>> stty: 'standard input': Inappropriate ioctl for device
>>>
>>> The first command is attached to a terminal (either a 'real' terminal, but
>>> more likely a pseudo-terminal), and shows its settings. The second
>>> command's stdin is the stdout of the echo command, and says so..
>>>
>>> Also check the tty command:
>>> $ tty
>>> /dev/pts/6
>>> $ echo dog | tty
>>> not a tty
>>>
>>> Marc
>>>
>>     But:
>>
>> | @08:49:08 ─▶leslie@pinto◀─
>> | wd=~/bin/NetRexx/Pipelines
>> | $ pipe 'command ls -l|console'
>> | total 224
>> | -rw-r--r-- 1 leslie users  3741 Jun 29 01:44 condense.class
>> | -rw-r--r-- 1 leslie users  1298 Jun 29 00:07 GenSymLinks.class
>> | -rw-r--r-- 1 leslie users  4688 Jun 28 23:53 GenSymLinks_gensymlinks.class
>> |    :
>> | -rw-r--r-- 1 leslie users  2403 Jun 19 15:50 treeOutput.txt
>> | rc=0
>>
>> works just fine, whereas
>>
>> | @08:49:20 ─▶leslie@pinto◀─
>> | wd=~/bin/NetRexx/Pipelines
>> | $ pipe 'command stty --all|console'
>> | rc=0
>>
>> produces no output.  What is the difference between the stage "command ls -l"
>> (which works) and "command stty --all" (which does not)?  We're not doing
>> bash redirection here; this is inside the NetRexx pipeline.
>>
>> Leslie