[gentoo-user] man bash document doesn't match real life bash.

[gentoo-user] man bash document doesn't match real life bash.

[David Harel]

Hi,

I was surprised to find that in man bash the reference to initialization
files is wrong. The bash manual says it reads initialization files from
/etc/profile:
FILES
       /bin/bash
              The bash executable
       /etc/profile
              The systemwide initialization file, executed for login shells


Where real life uses /etc/bash/bashrc
This part is taken from strace dump: strace bash -i
open("/etc/bash/bashrc", O_RDONLY|O_LARGEFILE) = 3

I use bash from gentoo package:
$ equery belongs /usr/share/man/man1/bash.1.bz2
[ Searching for file(s) /usr/share/man/man1/bash.1.bz2 in *... ]
app-shells/bash-3.2_p17 (/usr/share/man/man1/bash.1.bz2)

$ equery belongs /bin/bash
[ Searching for file(s) /bin/bash in *... ]
app-shells/bash-3.2_p17 (/bin/bash)


-- 
Regards.

David Harel,

==================================

Home office +972 77 7657645
Fax:        +972 77 7657645
Cellular:   +972 54 4534502
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Re: [gentoo-user] man bash document doesn't match real life bash.

[Neil Bothwick]

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On Wed, 19 Sep 2007 17:03:16 +0200, David Harel wrote:

> I was surprised to find that in man bash the reference to initialization
> files is wrong. The bash manual says it reads initialization files from
> /etc/profile:
> FILES
>        /bin/bash
>               The bash executable
>        /etc/profile
>               The systemwide initialization file, executed for login
> shells
> 
> 
> Where real life uses /etc/bash/bashrc
> This part is taken from strace dump: strace bash -i
> open("/etc/bash/bashrc", O_RDONLY|O_LARGEFILE) = 3

It reads both, this is from /etc/profile

if [ -n "${BASH_VERSION}" ] ; then
    # Newer bash ebuilds include /etc/bash/bashrc which will setup PS1
    # including color.  We leave out color here because not all
    # terminals support it.
    if [ -f /etc/bash/bashrc ] ; then
        # Bash login shells run only /etc/profile
        # Bash non-login shells run only /etc/bash/bashrc
        # Since we want to run /etc/bash/bashrc regardless, we source it
        # from here.  It is unfortunate that there is no way to do
        # this *after* the user's .bash_profile runs (without putting
        # it in the user's dot-files), but it shouldn't make any
        # difference.
        . /etc/bash/bashrc


-- 
Neil Bothwick

"Come on! It's a whole new life out there!"
"Oh, no. Not another one!"

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Re: [gentoo-user] man bash document doesn't match real life bash.

[Etaoin Shrdlu]

On Wednesday 19 September 2007, Neil Bothwick wrote:

> On Wed, 19 Sep 2007 17:03:16 +0200, David Harel wrote:

> > Where real life uses /etc/bash/bashrc
> > This part is taken from strace dump: strace bash -i
> > open("/etc/bash/bashrc", O_RDONLY|O_LARGEFILE) = 3
>
> It reads both, this is from /etc/profile
>
> if [ -n "${BASH_VERSION}" ] ; then
>     # Newer bash ebuilds include /etc/bash/bashrc which will setup PS1
>     # including color.  We leave out color here because not all
>     # terminals support it.
>     if [ -f /etc/bash/bashrc ] ; then
>         # Bash login shells run only /etc/profile
>         # Bash non-login shells run only /etc/bash/bashrc
>         # Since we want to run /etc/bash/bashrc regardless, we source
> it # from here.  It is unfortunate that there is no way to do # this
> *after* the user's .bash_profile runs (without putting # it in the
> user's dot-files), but it shouldn't make any # difference.
>         . /etc/bash/bashrc

It reads both, but the "Bash non-login shells run only /etc/bash/bashrc" 
behavior is not documented in man bash.
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Re: [gentoo-user] man bash document doesn't match real life bash.

[David Harel]

As Etaoin Shrdlu said, bash does not even start /etc/profile. Below grep
on strace output on bash:
$ grep profile /tmp/bash.trace
$
$ # My comment, it got nothing
$ grep bashrc /tmp/bash.trace
open("/etc/bash/bashrc", O_RDONLY|O_LARGEFILE) = 3
read(3, "# /etc/bash/bashrc\n#\n# This file"..., 2540) = 2540
open("/home/harel/.bashrc", O_RDONLY|O_LARGEFILE) = 3


Neil Bothwick wrote:
> On Wed, 19 Sep 2007 17:03:16 +0200, David Harel wrote:
>
>   
>> I was surprised to find that in man bash the reference to initialization
>> files is wrong. The bash manual says it reads initialization files from
>> /etc/profile:
>> FILES
>>        /bin/bash
>>               The bash executable
>>        /etc/profile
>>               The systemwide initialization file, executed for login
>> shells
>>
>>
>> Where real life uses /etc/bash/bashrc
>> This part is taken from strace dump: strace bash -i
>> open("/etc/bash/bashrc", O_RDONLY|O_LARGEFILE) = 3
>>     
>
> It reads both, this is from /etc/profile
>
> if [ -n "${BASH_VERSION}" ] ; then
>     # Newer bash ebuilds include /etc/bash/bashrc which will setup PS1
>     # including color.  We leave out color here because not all
>     # terminals support it.
>     if [ -f /etc/bash/bashrc ] ; then
>         # Bash login shells run only /etc/profile
>         # Bash non-login shells run only /etc/bash/bashrc
>         # Since we want to run /etc/bash/bashrc regardless, we source it
>         # from here.  It is unfortunate that there is no way to do
>         # this *after* the user's .bash_profile runs (without putting
>         # it in the user's dot-files), but it shouldn't make any
>         # difference.
>         . /etc/bash/bashrc
>
>
>   

-- 
Regards.

David Harel,

==================================

Home office +972 77 7657645
Fax:        +972 77 7657645
Cellular:   +972 54 4534502
Snail Mail: Amuka
            D.N Merom Hagalil
            13802
            Israel
Email:      hareldvd@ergolight-sw.com


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Re: [gentoo-user] man bash document doesn't match real life bash.

[Mrugesh Karnik]

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> Neil Bothwick wrote:
> > On Wed, 19 Sep 2007 17:03:16 +0200, David Harel wrote:
> >> I was surprised to find that in man bash the reference to initialization
> >> files is wrong. The bash manual says it reads initialization files from
> >> /etc/profile:
> >> FILES
> >>        /bin/bash
> >>               The bash executable
> >>        /etc/profile
> >>               The systemwide initialization file, executed for login
> >> shells
> >>
> >>
> >> Where real life uses /etc/bash/bashrc
> >> This part is taken from strace dump: strace bash -i
> >> open("/etc/bash/bashrc", O_RDONLY|O_LARGEFILE) = 3

Hmmm. bash -i is not a login shell. An interactive shell doesn't 
read /etc/profile if it's not a login shell.

From man bash:

``When  bash  is  invoked as an interactive login shell, or as a 
non-interactive shell with the --login option, it first reads and executes 
commands from the     file /etc/profile, if that file exists.  After reading 
that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in 
that order, and reads and executes commands from the first one that exists 
and is readable. The --noprofile option may be used when the shell is started 
to inhibit this behavior.

<snip>

When  an  interactive shell that is not a login shell is started, bash reads 
and executes commands from ~/.bashrc, if that file exists.  This may be 
inhibited by using the --norc option.  The --rcfile file option will force 
bash to read and execute commands from file instead of ~/.bashrc.''

-- 
----------------------------------------
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Public key on http://wwwkeys.pgp.net
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Re: [gentoo-user] man bash document doesn't match real life bash.

[Etaoin Shrdlu]

On Sunday 23 September 2007, Mrugesh Karnik wrote:

> From man bash:
>
> ``When  bash  is  invoked as an interactive login shell, or as a
> non-interactive shell with the --login option, it first reads and
> executes commands from the     file /etc/profile, if that file exists.
>  After reading that file, it looks for ~/.bash_profile, ~/.bash_login,
> and ~/.profile, in that order, and reads and executes commands from
> the first one that exists and is readable. The --noprofile option may
> be used when the shell is started to inhibit this behavior.
>
> <snip>
>
> When  an  interactive shell that is not a login shell is started, bash
> reads and executes commands from ~/.bashrc, if that file exists.  This
> may be inhibited by using the --norc option.  The --rcfile file option
> will force bash to read and execute commands from file instead of
> ~/.bashrc.''

And this last is the part that fails to mention that a non-login shell 
will read /etc/bash/bashrc before ~/.bashrc, as the comments 
inside /etc/bash/bashrc and David Harel say.

Ok, after closer inspection, it seems that the /etc/bash/ way is a 
gentooism. Bash would normally define SYS_BASHRC and SYS_BASH_LOGOUT 
as /etc/bash.bashrc and /etc/bash.bash_logout respectively, even though 
it does not use them by default (they are commented in the sources). 
Nearly all linux distros uncomment those definitions, thus making bash 
use those files (see eg ubuntu). A gentoo patch, namely 
bash-3.0-configs.patch, changes those into /etc/bash/bashrc 
and /etc/bash/bash_logout. See bug #26952 (esp. from comment #52) and 
bug #90488 for further details. Note that gentoo applies the patch 
regardless of the vanilla USE flag.

So, it seems that, after all, the standard man page is correct, but, in 
gentoo, it probably should be patched to reflect the way things work in 
gentoo. Not sure whether this is enough to be worth a bug report?
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Re: [gentoo-user] man bash document doesn't match real life bash.

[Albert Hopkins]

On Wed, 2007-09-19 at 17:03 +0200, David Harel wrote:
> I was surprised to find that in man bash the reference to
> initialization
> files is wrong. The bash manual says it reads initialization files
> from
> /etc/profile:
> FILES
>        /bin/bash
>               The bash executable
>        /etc/profile
>               The systemwide initialization file, executed for login
> shells 

Most bash installations have /etc/profile source /etc/bashrc.  This is
not uncommon.  You'll probably likely see the default ~/.bash_profile
source ~/.bashrc.

But it is sourcing /etc/profile else you wouldn't be getting half the
environment variables that you're getting.

-a

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