ps output line length change

Eric van Gyzen eric at vangyzen.net
Wed Feb 21 21:16:39 UTC 2018


On 02/16/2018 18:46, Mike Karels wrote:
> A couple of weeks ago, I sent email on the committers list proposing
> reversion of r314685 changing the output line length for ps.  In
> particular, it uses unlimited line length if stdout is not a tty.
> The previous code used the tty width if any of stdout, stderr, or
> stdin was a tty.  The change in r314685 has not been shipped in
> any release yet.
> 
> The responses to that email all agreed with reversion.  However, there
> has been some additional discussion in private email.  Therefore, I
> am sending this to arch at .
> 
> My reasoning is this;
> 
> 1. The output line length for the following commands should reasonably
> be the same in an interactive session: ps, ps | more, ps | grep.
> 
> 2. The previous behavior is the way things have worked since 1990,
> as Conrad pointed out.  As others pointed out, it has long been known
> that -ww was required to get unlimited lines, e.g. in a script.  I
> don't see any significant justification to change 28 years of precedent.
> 
> 3. The rationale for the change included that it is easier for scripts
> (which I maintain are broken if they assume this), and that it doesn't
> matter if using less with left-right scrolling.  We shouldn't make
> assumptions about what the output is going through, let alone assume
> left-right scrolling.  The previous algorithm was described as magic,
> but I think it is straightforward.  Perhaps a comment is in order.
> 
> I tried to think of a compromise solution, but the only thing that
> comes to mind is messy: an environment variable that would enable
> unlimited line length when the output was not a tty.  That would not
> be easier for scripts.  And as Bruce noted, aliasing ps to "ps -ww"
> does not work with old BSD-stype "ps axu".
> 
> What do people think should be done?

I agree that the change should be reverted.

Eric


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