My Shell Setup Suite

John Hurst

Version 1.9.7

20240402:091059

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.

1.1 Active Machines

These machines are maintained in active use.

• albury Ubuntu 22.04, virtual machine running on wodonga hardware.
• albens Ubuntu 14.04.03, cloud
• burnley Ubuntu 18.04, iMac 27"
• newport Ubuntu 18.04, PC, regular desktop
• reuilly Raspian 10, Raspberry Pi 4, spare
• spencer Ubuntu 18.04, ASUS, house and network server
• wiki.gwuc.org.au Ubuntu 16.04, cloud, church wiki server
• wodonga MacOS 14.3, current laptop replacing everton

1.2 Inactive Machines

Mostly operational, but turned off.

• bittern Mac OSX 10.6.8, Mac Book Pro 15", occasional laptop
• everton Ubuntu 18.04, dual boot Windows 10, HP Pavilion x360. Regular laptop, awaiting repair for failed power supply.
• jeparit Raspian 10, Raspberry Pi 4, spare
• kerang Debian GNU/Linux 7.4, Beagle Bone, low level house computer
• terang Raspian 10, Raspberry Pi 4, high level house computer

1.3 Decomissioned Machines

These machines do not have any future.

• auteuil Debian 7.4 wheezy, Beagle Bone
• dimboola Mac OSX 10.6.8, iMac 27"
• hamilton Max OSX 10.10.5, MacBook Pro Retina 13"
• heywood virtual Ubuntu running on hamilton
• in.gwuc.org.au MacOSX ?, church database computer
• lilydale Ubuntu 14.04.3, Acer 11"
• ouyen Ubuntu 20.04, Raspberry Pi 4 Model B
• wolseley Ubuntu 14.04.3, HP

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?

(pedantic note: one might be tempted to change that title to "Whom are we?", but note that the verb "to be" is copulative, meaning that it takes the nominative case for both subject and predicate.)

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 complains.

3.2 Where are we?

Crucial to the whole rigmarole of setting things up is knowing on what machine we are running. hostname is our friend here. If there is no hostname, then we are in deep do-dos.

For some strange reason, the expr program resides in a different place on Ubuntu systems. Find the right one.

The upshot is to set HOST as an abbreviated form of HOSTNAME, that is, without any domain qualification. Do this by extracting the prefix of ".". Note the new version of this, using the -s flag to hostname. It pays to read the manual! The old version follows, commented out.

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 5.11>.

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 3.4,3.5,3.6>.

MANPATH

The search path for man pages.

PATH

The search path for commands and binaries. See scrap <set paths on all machines 3.9,3.24>.

RSYNC_RSH

The rsh protocol to be used by rsync, currently set to ssh, and set in <set sundry environment variables 3.27>.

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.

ALBENS

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

ALBURY

The qualified domain name to reach albury from the current platform. This currently does not work outside wodonga.

BITTERN

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

BURNLEY

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

EVERTON

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

GWUC-WIKI

The qualified domain name to reach gwuc-wiki from the current platform.

KERANG

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

REUILLY

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

JEPARIT

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

SPENCER

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

TERANG

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

WODONGA

The qualified domain name to reach wodonga 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 bittern, dimboola, are all set in like fashion, as they all run Mac OS X.

Note that there are two personal bin directories for Linux systems:

1. $HOME/binln, which contains links specific to each architecture and machine for standard binaries, such as Python, which vary from machine to machine. For this reason, entries in this directory are excluded from backup and synchronization operations.
2. $HOME/bin, which contains non-architecture specific scripts, such as shell scripts and other high level programs. This directory is included in synchronization and backup operations.

The defaults settings assume that we are on a laptop (bittern, 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.

3.4 Set the PYTHONPATH

The python systems have different paths for different systems. Set them up here.

3.5 Set Background Colour

4. The Set Machine file

This script is intended to provide parameterizarion of all X Windows settings in one consistent place. Currently (20180115:130245) under development. The individual machine files follow.

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!

Note the bizarre behaviour here. I cannot define a function '+', since '+' is not a valid identifier. But '-' is. On the other hand, I cannot make an alias for '-', but I can for '+'. Work that one out.

At least, all's well that ends well.

20091020:094011 No, not really. While the script works as such, the Makefile barfs when it tries to execute (source?) the offending eval function line. Got no further clues at this stage.

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}.

{Note 6.1.1}

note: NO LEADING SPACES!

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

Empty, because we don't use TeX on these machines

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: The bash logout file

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.

Colour Allocation

ajh

Version 1.9.2

20200426:214029

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:

9.1 Obsolete Machines

These machines have been decomissioned, but their colours are recorded for posterity.

bastille was moved to 33ffcc to clarify distinction with dimboola

10. The Makefile

The Makefile handles the nitty-gritty of copying files to the right places, and setting permissions, etc.

Note the nifty use of an XLP literate program macro to handle the intricacies of installing files on different machines. The THISHOST variable is set to the non-qualified name of the machine, and used to check if we are copied to the local or a remote machine. Different copy operations are required in each case.

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 5.11>). 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.

20091020:093027 The list of files to install has been re-ordered, so that .bashrc appears last. It is the one causing the error, but it still seems to install correctly. By making it last, all the other (non-error making) ones get installed first.

	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. Default .bashrc

This code is the code supplied as default to .bashrc. It is included here for archival reasons, and to pick any bones that may be present.

12. Indices

12.1 Files

12.2 Chunks

12.3 Identifiers

13. Document History