.shrc

# Customise the shell environment for interactive sessions.

# Useful references:
#
# - Shell Command Language:
#   <http://pubs.opengroup.org/onlinepubs/000095399/utilities/xcu_chap02.html>.

## If not running interactively, don't do anything.
#[[ $- != *i* ]] && return
case $- in *i*) true ;; *) false ;; esac || return

## Add path to custom user shell scripts.
test -d "${HOME}/scripts" && PATH="${HOME}/scripts:${PATH}"

## Source aliases, if defined.
test -f ${HOME}/.profile.d/aliases.sh && . ${HOME}/.profile.d/aliases.sh

## Source functions, if defined.
test -f ${HOME}/.profile.d/functions.sh && . ${HOME}/.profile.d/functions.sh

##TODO Could the above (two) lines be replaced by:
## if test -d ${HOME}/.profile.d ; then
##   for script in ${HOME}/.profile.d/*.sh ; do
##     test -f ${script} && . ${script}
##   done
## fi

## Customise shell environment variables. See chapter 8, Environment Variables,
## of the POSIX Shell and Utilities Specification,
## <http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html>.

### Configure shell history
export HISTFILE="${HOME}/.sh_history"
export HISTSIZE=1000000

# Disable history file if running as root user.
if  test `id -u` = 0 ; then
  unset HISTFILE HISTSIZE
fi

### Define a custom user prompt to show hostname and current directory and to
### distinguish between root and normal users.
PS1='$(logname)@$(uname -n):$(pwd)>'

NORMAL="\[\e[0m\]"
RED="\[\e[1;31m\]"
GREEN="\[\e[1;32m\]"

#### if test "$(id -u)" -eq "0" <- More portable?
if test `id -u` = 0 ; then
  PS1="$RED$PS1$NORMAL "
else
  PS1="$GREEN$PS1$NORMAL "
fi

unset NORMAL
unset RED
unset GREEN

### Define PS4 for debugging?
#export PS4='[$LINENO]+'
#set -x

### Define default text editors
export EDITOR=nano
export VISUAL=emacs

### Internationalization: use British English and UTF-8
export LC_ALL="en_GB.UTF-8"
export LANG="en_GB"

### Prevent clobbering of existing files by the redirection operator.
set -o noclobber

### Bash specific customisations:
if test -n "${BASH_VERSION}" ; then
    # Ignore small directory name typos when changing directory.
    shopt -s cdspell

    # Append, rather than overwrite, history on exit.
    shopt -s histappend

    # Save multiline commands in a single history entry.
    shopt -s cmdhist

    # Erase duplicated entries in history file.
    export HISTCONTROL=ignoredups

    # Ignore some common commands.
    export HISTIGNORE="ls:cd:cd -:pwd:* --help"
fi