Bug 1329059

I cannot reproduce it on Fedora 23:

TERM=xterm
LESSOPEN=|/usr/bin/lesspipe.sh %s
ncurses-5.9-21.20150214.fc23.x86_64
ncurses-libs-5.9-21.20150214.fc23.x86_64
xterm-318-2.fc23.x86_64
less-481-1.fc23.x86_64
perl-Pod-Perldoc-3.25-347.fc23.noarch

Though I admit some people sometimes complained about the same issue. I would welcome reliable reproducer.

To the question: Yes, perldoc has "-t" argument that disables ANSI sequences on the output. I think "perldoc --help" is not so hard way to discover it.

I can fairly reproduce it with "perldoc -T perlreref | less".  The capital -T prints the output to stdout instead of sending it to a pager. But the perldoc (that I have, the behavior changes with various perldoc versions) feeds the pager from a temporary file. strace shows:

[pid  3367] execve("/usr/bin/less", ["less"], ["XDG_VTNR=1", "XDG_SESSION_ID=1", "SSH_AGENT_PID=2103", "HOSTNAME=dhcp-0-146.brq.redhat.c"..., "SHELL=/bin/bash", "TERM=xterm", "HISTSIZE=1000", "TERMPATH=/home/petr/.termcap:/et"..., "WINDOWID=65011747", "QTDIR=/usr/lib64/qt-3.3", "QTINC=/usr/lib64/qt-3.3/include", "XORG_RUN_AS_USER_OK=1", "USER=petr", "XTERM_SHELL=/bin/bash", "LS_COLORS=rs=0:di=01;34:ln=01;36"..., "SSH_AUTH_SOCK=/tmp/ssh-QUjk3MkTh"..., "PAGER=less", "PATH=/home/petr/bin:/usr/lib64/q"..., "MAIL=/var/spool/mail/petr", "_=/usr/bin/less", "QT_IM_MODULE=xim", "PWD=/home/petr", "XMODIFIERS=@im=SCIM", "EDITOR=/usr/bin/vim", "LANG=cs_CZ.UTF-8", "MODULEPATH=/etc/scl/modulefiles:"..., "LOADEDMODULES=", "HISTCONTROL=ignoredups", "XTERM_VERSION=XTerm(318)", "XTERM_LOCALE=cs_CZ.UTF-8", "HOME=/home/petr", "XDG_SEAT=seat0", "SHLVL=5", "LESS=-R", "LOGNAME=petr", "CVS_RSH=ssh", "QTLIB=/usr/lib64/qt-3.3/lib", "MODULESHOME=/usr/share/Modules", "LESSOPEN=|/usr/bin/lesspipe.sh %"..., "WINDOWPATH=1", "XDG_RUNTIME_DIR=/run/user/500", "DISPLAY=:0.0", "GTK_IM_MODULE=scim", "XAUTHORITY=/home/petr/.Xauthorit"..., "CCACHE_HASHDIR=", "BASH_FUNC_module()=() {  eval `/"..., "BASH_FUNC_scl()=() {  local CMD="...]) = 0

I suspect perldoc sets LESS=-R. I dont' have the variable in my environment:

$ set |grep LESS
LESSOPEN='|/usr/bin/lesspipe.sh %s'

"perldoc -T perlreref | LESS=-R less" works for me.

From my point of view, perldoc is fine in Fedora. This is issue in RHEL-7's perldoc.

Actually I cannot reproduce it in RHEL-7 either. Thought it works there probably for some other reason. If you want to open a bug for RHEL-7, I need the reproducer.

(In reply to Petr Pisar from comment #1)
> I cannot reproduce it on Fedora 23:

I feel I'm facing some magic, because I'm not able to reproduce this on F23
neither, *now*.

> To the question: Yes, perldoc has "-t" argument that disables ANSI sequences
> on the output. I think "perldoc --help" is not so hard way to discover it.

The question is whether it would be possible to not print terminal sequences
*by default*;  not how it can be done.  But yes -- as it obviously works on
F23, there is no need to change anything.
 
> I suspect perldoc sets LESS=-R. I dont' have the variable in my environment:

That's right.
 
> From my point of view, perldoc is fine in Fedora. This is issue in RHEL-7's
> perldoc.

Correct.

(In reply to Petr Pisar from comment #2)
> Actually I cannot reproduce it in RHEL-7 either. Thought it works there
> probably for some other reason. If you want to open a bug for RHEL-7, I need
> the reproducer.

In RHEL7, I'm able to reproduce it.  Perldoc does not set the LESS variable,
can be debugged by:

  $ cat lesswrap
  #! /bin/sh
  env | grep -i less
  less "$@"

  $ PAGER=./lesswrap perldoc perlreref

Petr, can you confirm?

(In reply to Pavel Raiskup from comment #3)
> In RHEL7, I'm able to reproduce it.  Perldoc does not set the LESS variable,
> can be debugged by:
> 
>   $ cat lesswrap
>   #! /bin/sh
>   env | grep -i less
>   less "$@"
> 
>   $ PAGER=./lesswrap perldoc perlreref
> 
> Petr, can you confirm?

While, of course, you can use:

  $ PERLDOCDEBUG=1 PAGER=./lesswrap perldoc perlreref
  $ # hit the CTRL^Z
  $ # open the temp file generated by perldoc to see that the color sequences
    # are there.

Yes, in RHEL-7 if the PAGER is defined, then the ANSI sequences are not interpreted.