Re: [Help-bash] procps output truncated due to bash setting $COLUMNS

[Steven W. Orr]

On 1/8/2013 1:14 PM, Bob Proulx wrote:
> Jan Engelhardt wrote:
> > Pierre Gaston wrote:
> > > Bash sets COLUMNS when interactive, but it does not export it so it
> > > should not interfere with other tools unless it is exported in one of
> > > your startup files.
> >
> > Hrrrm.
> >
> > 17:57 nakamura:~ > unset LINES COLUMNS
> > 17:57 nakamura:~ > perl -le 'print $ENV{COLUMNS}'
> >
> > 17:57 nakamura:~ > bash --noprofile --norc
> > bash-4.2$ perl -le 'print $ENV{COLUMNS}'
> > 80
> >
> > It would seem it exports it by default.
>
> I cannot recreate that result.
>
>    $ echo $COLUMNS
>    80
>    $ printenv COLUMNS
>    ...nothing...
>
>    $ echo $BASH_VERSION
>    4.2.37(1)-release
>
>    $ echo $BASH_VERSION
>    4.1.5(1)-release
>
> Bob

Look in your init file (*all* of them). Look for things like:

alias rs='set noglob; eval `resize -u`'; unset noglob
or
xsize() {
  set -- $(stty size)
  export LINES=$1
  export COLUMNS=$2
  xtitle
}

or

PROMPT_COMMAND=xsize

Something is doing something.

Also, bash --noprofile --norc, I don't believe is an insulator of environment 
variables leaking through. A proper test *might* be

env - bash --noprofile --norc

but that doesn't work for me either. I still get them set but they are *not* 
environment variables. They are just locals. Same result with or without the 
env -.

502 > env - bash --noprofile --norc
bash-4.2$ env | egrep 'LINES|COLUMNS'
*bash-4.2$ set | egrep 'LINES|COLUMNS'
COLUMNS=80
LINES=24
bash-4.2$ perl -le 'print $ENV{COLUMNS}'

bash-4.2$


I do see this in the man pages:


       COLUMNS
              Used by the select compound command to  determine  the  terminal
              width  when  printing  selection  lists.  Automatically set upon
              receipt of a SIGWINCH.

       LINES  Used by the select compound  command  to  determine  the  column
              length  for  printing  selection  lists.  Automatically set upon
              receipt of a SIGWINCH.

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