Here is a good example from ksh .profile for Solaris

################################################################################
# Name: .profile
# Description: This is root's profile. Login shells source this after
# /etc/profile. It is used to define root's environment.
# All non-environment configuration will be done in the
# shell specific resource file.
# Special: ENV= is specific to ksh to indicate the name of it's
# resource file. Bourne shell ignores this.
# Author: Ryan T. Tennant
# Version: 0.1
# Date: 2000/08/09
#
################################################################################

default_paths() {
PATH="/usr/bin:/usr/sbin:/sbin:/usr/local/bin"
MANPATH="/usr/man:/usr/local/man"
LD_LIBRARY_PATH="/usr/lib:/usr/local/lib"
OS="`/usr/bin/uname -s | /usr/bin/grep -ci sun`"
}

check_openwindows() {
if [ -d /usr/openwin ]; then
PATH="$PATH:/usr/openwin/bin:/usr/dt/bin"
MANPATH="$MANPATH:/usr/openwin/man:/usr/dt/man"
LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/openwin/lib:/usr/dt/lib"
fi
}

check_build_environment() {
if [ -d /usr/ccs ]; then
PATH="$PATH:/usr/ccs/bin"
LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/ccs/lib"
fi
}

check_online_disk_suite() {
if [ -d /usr/opt/SUNWmd ]; then
PATH="$PATH:/usr/opt/SUNWmd/sbin"
MANPATH="$MANPATH:/usr/opt/SUNWmd/man"
fi
}

check_veritas_volume_manager() {
# Version 2.x
if [ -x /opt/VRTSvxva/bin/vxva ]; then
PATH="$PATH:/opt/VRTSvxva/bin"
MANPATH="$MANPATH:/opt/VRTSvxva/man"
fi

# Version 3.x
if [ -x /opt/VRTSvmsa/bin/vmsa ]; then
PATH="$PATH:/opt/VRTSvmsa/bin"
MANPATH="$MANPATH:/opt/VRTSvxvm/man:/opt/VRTSvmsa/man"
fi
}

check_sun_ent_volume_manager() {
if [ -d /opt/SUNWvxva ]; then
PATH="$PATH:/opt/SUNWvxva/bin"
MANPATH="$MANPATH:/opt/SUNWvxvm/man:/opt/SUNWvxva/man"
fi
}

check_naviscore() {
if [ -d /opt/CascadeView ]; then
. /opt/CascadeView/etc/cvdb.cfg
. /opt/CascadeView/etc/cascadeview.cfg
. /opt/sybase/.sybenv

PATH="$PATH:/opt/OV/bin"
XUSERFILESEARCHPATH="/opt/CascadeView/app-defaults/%N:$XUSERFILESEARCHPATH"

export XUSERFILESEARCHPATH
fi
}

check_networker() {
if [ -d /usr/bin/nsr ]; then
PATH="$PATH:/usr/bin/nsr:/usr/sbin/nsr"
fi
}

check_cluster() {
if [ -d /opt/SUNWcluster ]; then
PATH="$PATH:/opt/SUNWcluster/bin"
MANPATH="$MANPATH:/opt/SUNWcluster/man"
fi
}

generate_paths() {
default_paths
check_openwindows
check_build_environment
check_online_disk_suite
check_veritas_volume_manager
check_sun_ent_volume_manager
check_naviscore
check_networker
check_cluster
}

set_options() {
case "$1" in
*ksh)
EDITOR="vi"
ENV=".kshrc"
HOSTNAME=`/usr/bin/uname -n | /usr/bin/cut -d. -f1`
PAGER="/usr/bin/more"
if [ $OS -gt 0 ]; then
USER=`/usr/xpg4/bin/id -un`
else
USER=`id -un`
fi
;;
*sh)
EDITOR="vi"
HOSTNAME=`/usr/bin/uname -n | /usr/bin/cut -d. -f1`
PAGER="/usr/bin/more"
cd() {
chdir $*
set_prompt `basename $0`
}
if [ $OS -gt 0 ]; then
USER=`/usr/xpg4/bin/id -un`
else
USER=`id -un`
fi
;;
esac
}

set_prompt() {
case "$1" in
-ksh)
PS1='[$USER@$HOSTNAME]:$PWD
# '
;;
-sh)
PWD=`pwd`
PS1="[$USER@$HOSTNAME]:$PWD
# "
;;
esac
}

export_environment() {
export ENV PAGER HOSTNAME LD_LIBRARY_PATH MANPATH PAGER PATH PS1
}

# begin environment

generate_paths
set_options "$0"
set_prompt "$0"
export_environment

# proceed to $ENV for ksh resources

Keep Ryan's name in it - he did write it afterall.