My Shell Setup Suite

John Hurst

Version 1.5.4

20080312:092253

Abstract

Table of Contents

1. Introduction

This document describes the files used to set up the appropriate working environment for using the bash shell. They are intensely personal, and anyone reusing this document for their own purposes will also certainly want to modify this document.

Permission is given to reuse this document, provided that the source is acknowledged, and that any changes are noted in the documentation.

The document is in the form of a literate program, and generates all files necessary to maintain the working environment, including a Makefile.

These files have been edited from equivalent tcsh originals, but not all features of that shell have been mirrored in here.

2. Literate Data

This message gets used in a number of places to ensure that all modifications are focussed through this document.

3. The Profile file .bash profile

The .bash_profile file is executed automatically by login shells. It has the responsibility to set the path (and other variables), run the .bashrc file (because a login shell doesn't do that automatically), and initialize the prompt with an explicit call to bash-prompt. I also worry about the initial login shell, since that has to do slightly different things (such as setting window title bars, and clearing up when logging out).

3.1 Who are we?

We often need to know in this script whether we are logging in as ajh or as root. This code chunk sets the global variable $user appropriately, or dies.

3.2 Where are we?

HOST is the abbreviated form of HOSTNAME, that is, without any domain qualification.

3.3 Set Environment Variables

The variables that we set are

ASSOCDB

Defines the absolute pathname to the assoc program's database file. It is currently set to /home/ajh/assoc/files, and set in <set sundry environment variables >.

HEADING

Filename to record what is displayed at the head line of the window. This is modified by process number to ensure that each window is handled independently. See scrap <set heading 5.10>.

HOST

The leading word (non-`.' characters) of the full hostname. For example, if HOSTNAME gives central.cs.monash.edu.au, return just central. See scrap <determine where we are 3.3>.

MANPATH

The search path for man pages.

PATH

The search path for commands and binaries. See scrap <set paths on all machines 3.5,3.22>.

PILOTPORT

The port used by the pilot software, and set in <set sundry environment variables 3.25>

RSYNC_RSH

The rsh protocol to be used by rsync, currently set to ssh, and set in <set sundry environment variables 3.25>.

SERVER

The name of the server machine.

BGCOLOUR

The background colour for this machine (see section Window Colours)

PYTHONPATH

The path to search for Python libraries.

ARARAT

The qualified domain name to reach ararat from the current platform.

BALLARAT

The qualified domain name to reach ballarat from the current platform.

MURTOA

The qualified domain name to reach murtoa from the current platform.

RAINBOW

The qualified domain name to reach rainbow from the current platform.

The sundry variables are set first, since some of them may be used to set the path variable.

3.3.1 Set the PATH variable

Note that the paths are established in increasing order of precedence, that is, the last paths defined are found first.

The machines ararat, ballarat, bendigo, murtoa, clematis and rainbow are all set in like fashion, as they all run Mac OS X (even tho' murtoa and clematis are Intel Macs).

dhcp7-218 was added during my OSP at Swinburne, since that was the hostname automatically generated by the DHCP connection.

The defaults settings assume that we are on a laptop (ararat, but either no hostname, or foreign hostname), so that we go for the standard Mac OS X settings.

Now empty, but kept for future use.

Set the environment variable RSYNC_RSH, which defines the shell transport for rsync as the secure shell ssh.

dhcp7-218 is the machine id allocated at Swinburne (study leave, 2005). It can be removed post 31 Dec 2005.

Currently, only murtoa is set up for ciao prolog

Now work out what value to assign to SERVER. This is currently kludged, since there is no direct way of knowing what is at the other end of the wire for remote connections. We assume that at home we are using central, and at work we are using hawthorn.

We pick up whether the DISPLAY variable ends with a non-zero window number. This is used by ssh to indicate a remote server. If DISPLAY does indicate a remote server, we use the value of HOST to select the complementary machine (indy03 for host central, and vice versa) and assign that to SERVER. If DISPLAY indicates a local server, then just use the value of HOST as the value of SERVER.

3.4 Set Background Colour

4. The Set Machine file

This simple little script ensures that the X initialization and default files point to the right place.

5. The Bash Resource Control file .bashrc

The .bashrc file is read every time a bash shell is started. For interactive shells, we need to set the aliases and the prompt.

5.1 Define aliases

{Note 5.2.1}

Note that the argument to pushd in the definition of + must be quoted, to avoid problems with directories names containing embedded spaces. But we also have to be careful with empty parameters!

5.2 Define the shell prompt

I like the prompt to show what directory I'm in, as well as the usual login and machine names. Throw in the history number for good measure. But don't set the prompt command if we are in the primary login shell, since it fouls up the window title and/or prompt.

This shell script is because bash does not have the equivalent of cwdcmd that tcsh has. So we set up the PROMPT_COMMAND variable to execute this script, which looks at the current heading, the current directory, and sees whether an explicit repainting of the window title bar is necessary.

5.3 Determine if Primary Login

This code used to be called from .bash_profile, but key environment variables were not set at this stage. Hence it is now invoked in .bashrc.

We need to know if we are in the primary login shell. This may be different for various machines, since some may be xdm driven, while others just give a tty login. The outcome of this code is to set the variable LOGINLVL to 0 if we are at the primary login level, 1 otherwise.

5.4 The bash-prompt file

The bash-prompt file does cool things like set the window title to the path name of the current directory. It is programmed as a separate executable file, due to bash's idiosyncracies (it can be done as an alias in cshrc).

The following wonderful piece of code is the magic to set the X windows title bar to the host name and directory, in the format HOST:directory for the full window, and HOST:basename for the iconified form.

However, since we cannot enter the character sequence directly, the code must be translated subsequently to include the escape characters. This is done in the Makefile, by translating the temporary file bash-p to bash-prompt.

6. .texrc The TeX Resource Control file

This file is responsible for setting environment variables to enable {\TeX} to run. I've made it a separate file, so that it can be sourced from other places as necessary to use {\TeX}.

20050725:160750 Removed the TEXFORMATS path to my local formats directory. This is now handled in the ~/lib/texmf directory.

7. .sgmlrc The SGML Resource Control file

This file is responsible for setting environment variables to enable SGML and related programs to run. I've made it a separate file, so that it can be sourced from other places as necessary to use SGML.

8. Logging out: .bash_logout

Remove the window heading file for this process, and clean up all the window heading and counting files if we are at the bash shell level.

Kill any rootimage (background image) process.

9. Window Colours

This section is defined here not so much because it is used by this suite, as because it seems the best place to define what are system wide resources, used in a range of applications. Cut and paste the following definitions as required.

For reference:

10. The Makefile

I had to kludge the bash-prompt construction. Since it relies upon two control characters that foul up this literate program, they are represented by the strings {esc} and {bel} respectively in the bash-prompt template file, bash-p (See <set heading >). A sed script in the Makefile trans-esc-bel then does the magic of converting these to the real thing. The definitions of the shell variables e and b allow us to manipulate the otherwise unrepresentable control characters. Each of these is formed by translating a dummy character into the control character.

This was the entry in the Makefile, but it doesn't appear to work.

	e=`echo e | tr e '\033'` \
	b=`echo b | tr b '\007'` \
	sed -e "s/{esc}/$$e/g" -e "s/{bel}/$$b/g" bash-p >bash-prompt

11. Indices

11.1 Files

11.2 Chunks

11.3 Identifiers

Document History

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