From: Karel Zak <kzak@xxxxxxxxxx>
Subject: Re: [PATCH 3/7] lsfd: improve grammar, and use angular brackets around placeholder word
Date: Thu, 24 Apr 2025 12:05:07 +0200
> On Thu, Apr 24, 2025 at 06:55:05PM +0900, Masatake YAMATO wrote:
>> > Also, use dots instead of "(s)" to indicate possible multiple arguments,
>> > and don't use "<when>" when the possible arguments differ from "always",
>> > "never", "auto".
>> >
>> > Signed-off-by: Benno Schulenberg <bensberg@xxxxxxxxxx>
>> > ---
>> > lsfd-cmd/lsfd.c | 6 +++---
>> > 1 file changed, 3 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/lsfd-cmd/lsfd.c b/lsfd-cmd/lsfd.c
>> > index 2eb53935c..3610de8dd 100644
>> > --- a/lsfd-cmd/lsfd.c
>> > +++ b/lsfd-cmd/lsfd.c
>> > @@ -2190,14 +2190,14 @@ static void __attribute__((__noreturn__)) usage(void)
>> > fputs(_(" -o, --output <list> output columns (see --list-columns)\n"), out);
>> > fputs(_(" -r, --raw use raw output format\n"), out);
>> > fputs(_(" -u, --notruncate don't truncate text in columns\n"), out);
>> > - fputs(_(" -p, --pid <pid(s)> collect information only specified processes\n"), out);
>> > + fputs(_(" -p, --pid <pid>... collect information only for specified processes\n"), out);
>>
>> This change implies that --pid 1 2 3 works.
>> However, specifying multiple pids to one --pid doesn't work.
>>
>> # lsfd --pid 1 $$
>> Try 'lsfd --help' for more information.
>>
>> Only --pid "1 2 3" or works. See double-quote chars.
>>
>> # lsfd --pid "1 $$"
>
> It also supports comma, it means --pid 1,2,3
>
> It would be better to not announce that space is possible to use as
> separator, and use comma in the help and man page
>
> fputs(_(" -p, --pid <list> restrict to specified processes (command separated pids)\nn"), out);
>
> or so ...
I added code supporting whitespace as a separator for combining lsfd with
pidof, as I wrote as an example in lsfd(1):
# lsfd --pid "$(pidof firefox)"
The idea combining with pidof comes from strace.
The -p option of strace supported whitespace as a separator.
So we can run strace with pidof like:
# strace -p "$(pidof firefox)"
I didn't know this smart feature.
So I added -S option, an option for specifying separator to pidof ago.
$ pidof -S ' -p ' zsh
4185021 -p 4161716 -p 4156470 -p 4155385
$ strace -p $(pidof -S ' -p ' zsh)
https://gitlab.com/procps-ng/procps/-/commit/73492b182dc60c1605d1b0d62de651fad97807af
https://lists.strace.io/pipermail/strace-devel/2018-March/007950.html
https://lists.strace.io/pipermail/strace-devel/2018-March/007951.html
https://lists.strace.io/pipermail/strace-devel/2018-March/007952.html
That was a small thing but impressive study for me.
Simplifying the output of --help is nice
However, from the man page, I want to keep the description of -p
supporting whitespace as a separator.
Masatake YAMATO
> Karel
>
> --
> Karel Zak <kzak@xxxxxxxxxx>
> http://karelzak.blogspot.com
>
