#!/bin/sh
#
# locate_script -- Find a scripts location (for self doc, or configs)
#
# Small Script you can add to the beginning of your shell programs to 
# determine the location of the script.  This lets you find things like
# configuration files relative to the scripts location, or read the script
# itself for things like self-documenting manuals (something I do a lot).
# 
# It has worked for me for more than 30 years! And I have used it on
# Sun3, Sun4, Ultrix, Solaris, Linux, MacOSX, with bourne shells, dash, 
# bash, ksh, and zsh.  It should work for any Unix-like environment.
# 
# Technically locating a running script has no solution, as it could be a 
# piped into a shell, but in practice it does work.
#
# See BASHFAQ:   http://mywiki.wooledge.org/BashFAQ/028
#
###
#
# Simple -- Just the program name
#PROGNAME=`basename $0` # Program basename (not $0 may not be good!)
#PROGDIR=`dirname $0`   # directory of script (may be relative)
#
# For BASH ONLY
PROGNAME="${BASH_SOURCE##*/}"    # script name (basename)
PROGDIR="${BASH_SOURCE%/*}"      # directory (dirname - may be relative)

# OLD Discover where the shell script resides
#PROGNAME=`type "$0" | awk '{print $3}'`  # ask the shell 
#PROGDIR=`echo $0 | sed -e 's,[\\/][^\\/][^\\/]*$,,'`

echo "ARG ZERO      : $0"
echo "GIVEN NAME    : $BASH_SOURCE"
echo "PROGNAME      : $PROGNAME"
echo "PROGDIR       : $PROGDIR"

if [ ! -f "$PROGDIR/$PROGNAME" ]; then # This has NEVER happened to me!
   echo >&2 "$PROGNAME: Unable to locate the script -- ABORTING"
   exit 10
fi

# Fully qualify directory path (remove relative components and symlinks)
# This is important if you plan to change directories.
# if "type"
# NOTE: bash "pwd" only returns the users 'logical path' though symlinks.
# But "pwd -P" works as a bash builtin, or as a binary command
PROGDIR=`cd "$PROGDIR" && pwd -P || echo "$PROGDIR"`
ORIGDIR=`pwd -P`

# Using  "readlink -f"  if available.
# It is not a bash built-in, and is NOT available on MacOS (Arrgghh)
#ORIGDIR=`readlink -f .`
#PROGDIR=`readlink -f "$PROGDIR"`

echo "QUALIFIED DIR : $PROGDIR"
echo "ORIGINAL FROM : $ORIGDIR"

# -------------------------------------------------
# Now what do you want to do?

# Where do you want to be running?
# Caution: Any user provided file arguments should be accessed
# relative to the original directory $ORIGDIR and not to $PROGDIR
#cd "$PROGDIR"

# Get a config file relative to scripts location (without cd)
# config="$PROGDIR/../etc/$PROGNAME.conf"
# config=`readlink -f "$config"`     # clean up path

# -------------------------------------------------

Usage() {  # Report error and Synopsis line only
  echo >&2 "$PROGNAME:" "$@"
  sed >&2 -n '1,2d; /^###/q; /^#/!q; /^#$/q; s/^#  */Usage: /p;' \
          "$PROGDIR/$PROGNAME"
  echo >&2 "For help use  $PROGNAME --help"
  exit 10;
}
Help() {   # Output Full header comments as documentation
  sed >&2 -n '1d; /^###/q; /^#/!q; s/^#//; s/^ //; p' \
          "$PROGDIR/$PROGNAME"
  exit 10;
}
Error() {  # Just output an error condition and exit (no usage)
  echo >&2 "$PROGNAME:" "$@"
  exit 2
}

echo ""


# -------------------------------------------------