| Table 1. BIRCH hierarchical
directory structure (for simplicity, not all directories are shown). |
/home/birchadmin |
The BIRCH home directory
BIRCH is organized as described in Table 1. In the example, BIRCH is
located in '/home/birch'. A sample of directories is shown. The
location
of the BIRCH home directory is set in the environment variables $BIRCH
and $birch, which will be used throughout this document. "$BIRCH" is
generally used for readability in documentation, while "$birch" is
easier to type.
Local customizations are contained in a
separate directory, allowing easy upgrades.
The high-level organization of BIRCH is borrowed from Unix. All Unix
systems have standard system directories, and a directory called
/usr/local. /usr/local contains directories such as /usr/local/bin/,
usr/local/lib etc. Ideally, the system adminiatrator would add new
programs only to /usr/local, and not to other directories such as
/bin or /lib, which can be thought of as belonging to the operating
system. Consequently, upgrades of the operating system shouldn't affect
anything in /usr/local/, and changes to installed software
shouldn't affect the operating system.
Similarly, the high-level structure of BIRCH is mirrored in
$BIRCH/local. With very few exceptions, the local BIRCH
administration should never have to make changes in directories
other than $BIRCH/local. More importantly, programs and
documentation added $BIRCH/local are not clobbered when BIRCH is
upgraded to a new version.
| Table
2. Summary of BIRCH directories |
|
| Directory |
Description |
| admin |
files and scripts related to BIRCH administration |
| bin-os-hardware |
executable binaries, specific for a particular
operating system and hardware platform |
| dat |
ancilliary datafiles used by programs |
| doc |
documentation |
| install |
working directory for installation tasks |
| install-birch |
working directory for initial installation of
BIRCH system |
| java |
Java applications |
| lib-os-hardware | libraries, specific for a particular operating system and hardware platform |
| local |
locally-installed software, libraries,
documentation etc. |
| manl |
Unix-style manual pages for BIRCH software |
| pkg |
packages that need to be kept together in a
specific directory structure |
| public_html |
BIRCH Web pages |
| script |
(presumably) platform-independent scripts. When
possible, scripts are installed here, rather than being duplicated
several times in independent platform-specific bin directories |
| tutorials |
BIRCH tutorials |
The BIRCH system administrator should never
have to make changes on individual user accounts
In order to use the programs and datafiles in BIRCH, environment
variables need to be set when a user logs in. Most importantly, the
directories containing executable files must be added to the $PATH.
As well, enviroment variables governing how different programs work
must also be set. The exact mechanism for how these settings are
made when a user logs in depends on their default shell, as summarized
in the table below:
| Family |
The BOURNE shell family |
The C-shell family |
| shell executable |
/bin/sh, /bin/ash, /bin/ksh, /bin/bash, /bin/zsh |
/bin/csh, /bin/tcsh |
| files in $HOME directory |
.profile - executed at login and when starting a
new process |
.cshrc - executed at login and when starting a
new process .login -executed at login only |
For example, if a user's default shell is /bin/sh, then $HOME/.profile will be run at login time. Likewise, if a user's default shell is /bin/csh, then $HOME/.cshrc, followed by $HOME/.login, will be run at login.
To avoid the nightmare in which each user has to modify and update
these files themselves, it is imperative that settings be centrally
administered and automatically set for the user. To make this work, a
few changes must be made to each user's account. When the user runs
$BIRCH/admin/newuser, the following line is copied from
$BIRCH/local/admin/add_to_login to the user's .login file:
source birch_home_dir/admin/login.source
Similarly, the following line is copied from $BIRCH/local/admin/add_to_cshrc to the user's .login file:
source birch_home_dir/admin/cshrc.source
Finally, the following line is copied from $BIRCH/local/admin/add_to_profile to the user's .profile, .bash_profile and .bash_login files:
. birch_home_dir/admin/profile.source
Thus, regardless of the user's default shell, the correct
environment variables will be set.
| Note: If you have root access,
it is possible to eliminate the need for
users
to run the newuser script. Simply add the contents of
admin/add_to_cshrc, add_to_login and add_to_profile, respectively, to
the systemwide cshrc, login and profile scripts. All users on the
system will have the complete set of BIRCH environment variables. This
should probably be done after you have gotten BIRCH installed and
working. |
ORDER OF EVENTS: The C-shell Family
ORDER OF EVENTS: The Bourne Shell Family