Umask and redhat (updated)

[Rick Stevens]

Waldher, Travis R wrote:
>  
> 
> 
>>-----Original Message-----
>>From: Rick Stevens [mailto:rstevens at vitalstream.com] 
>>Sent: Friday, July 16, 2004 3:43 PM
>>To: Getting started with Red Hat Linux
>>Subject: Re: Umask and redhat (updated)
>>
>>Waldher, Travis R wrote:
>>
>>> 
>>>
>>>
>>>
>>>>-----Original Message-----
>>>>From: Rick Stevens [mailto:rstevens at vitalstream.com]
>>>>Sent: Friday, July 16, 2004 2:54 PM
>>>>To: Getting started with Red Hat Linux
>>>>Subject: Re: Umask and redhat (updated)
>>>>
>>>>
>>>>
>>>>>What if your shell is chsrc, or something other than bash.  
>>>>
>>>>Will this
>>>>
>>>>
>>>>>be set for them as well?
>>>>
>>>>For csh users, the lines are virtually identical in /etc/csh.cshrc.
>>>
>>>
>>>Ok, so basically there is no true global setting, I need to 
>>
>>set it for 
>>
>>>each type of shell?
>>
>>Yes, unfortunately.  This is due to the way the shells start 
>>up.  bash starts up by reading, in order, /etc/profile, 
>>/etc/bashrc, and ~/.bashrc among others.  csh starts by 
>>reading /etc/csh.cshrc, /etc/csh.login, and ~/.[t]cshrc and a 
>>host of others.
>>
>>This is all due to the various permutations of Unix out there 
>>(Linux being just one more), and not all of which behave the same.
>>
>>HISTORY LESSON:  The first Unix shell was called, aptly 
>>enough, "sh" and was written by a chap named Bourne.  It's 
>>more correctly called the "Bourne Shell".  "bash" is an 
>>enhanced version of the Bourne shell, named the "Bourne Again 
>>Shell" (cute, eh?).
>>
>>If you've ever wondered why all the system admin scripts are 
>>written for the Bourne or bash shells, the Unix standards 
>>state that the only shell you're guaranteed to have on a 
>>system is some variation of Bourne.  You are also guaranteed 
>>to have some other programs such as sed, ls, awk, grep, ls, 
>>rm, mv, mount and cp.  If you've ever wondered why those are 
>>in /bin (on the root filesystem), now you know--you can be 
>>sure that the root filesystem is mounted by the boot loader 
>>when your admin script is run.
>>
>>You aren't guaranteed of anything else at this early stage of 
>>your boot process.  csh, ksh, tsh and the rest may or may not 
>>be installed or on filesystems that aren't mounted yet.  If 
>>your script absolutely MUST work (e.g. to boot the system 
>>up), you must write it for Bourne/bash.
>>
>>Ok, RECESS TIME!  Who's up for a game of softball? :-)
> 
> 
> Ok.. So I tried making the changes, and nothing took effect, until I
> added some files to my home directory.  Which tells me that at least ES
> 3.0 is reading files in the following order:
> 
> /etc/profile
> /home/travis/.bash_profile
> /home/travis/.bashrc
> /etc/bashrc
> 
> If .bash_profile doesn't exist under my home account, the .bashrc script
> won't run, the .bashrc script calls /etc/bashrc.

The man page states:

When  bash is invoked as an interactive login shell, or as a non-inter-
active shell with the --login option, it first reads and executes  com-
mands  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.

> The question becomes, short putting this entry in the /etc/profile file,
> how can I ensure umask is always run, even if there isn't any startup
> scripts in the users home directory?

The only thing guaranteed to be read at login is /etc/profile--and that
isn't read if it isn't an interactive shell.  The last thing
/etc/profile does is run all "/etc/profile.d/*.sh" scripts, so you could
bury the umask stuff in there, but it still won't do anything if
/etc/profile isn't read.

With non-interactive shells (e.g. crontab entries), the value of
"$BASH_ENV" is executed instead of /etc/profile.  By default, that's
set to "~username/.bashrc".

> 
> Thanks,
> Travis
> 
> 
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-- 
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-             To iterate is human, to recurse, divine.               -
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