#!/bin/ksh
##############################################
## Prints abridged working directory path in form "head...tail"
## Usage: PWD [TEXT]
##   TEXT       The string to abridge (defaults to current path, $PWD or `pwd`)
##   $PWD_HEAD  Show this many leading characters from given text (default 10)
##   $PWD_TAIL  Show this many trailing characters from given text (default 20)
## 
## Attempts to tilde syntax for home directories, like $HOME/../user = ~user
## Great for use in $PS1, like:   export PS1='\u@\h $(PWD \w)\$ '
## 
## PWD 2.1, Copyright (c) 2002-8 by Adam Katz <scripts@khopis.com>, GPL
##############################################

[ "$1" = "--help" ] && \
  grep '^## ' `which $0 2>/dev/null || echo $0` |sed 's/^...//' && exit

# defaults
a=10 b=20 c=33
[ -n "$*" ] && TEXT="$*" || TEXT="$PWD" # ksh does links wrong; use bash or $1
[ -z "$TEXT" ] && TEXT=`pwd`
if [ -n "$PWD_TAIL$PWD_HEAD" ]; then
  [ -n "$PWD_HEAD" ] && expr $PWD_HEAD + 1 >/dev/null 2>&1 && a="$PWD_HEAD"
  [ -n "$PWD_TAIL" ] && expr $PWD_TAIL + 1 >/dev/null 2>&1 && b="$PWD_TAIL"
  c="$(expr $a + $b + 3)"
fi

# set up other users' home directories
# zsh actually does this already, only translate real paths, need to read passwd
if [ "$SHELL" != "/bin/zsh" ] && [ -r "$TEXT" ] && [ -r /etc/passwd ]; then
  for hdir in `grep '/bin/..*sh$' /etc/passwd |awk -F ':' '{printf $6":"$1" "}'` ":$HOME"
  do
    echo "$hdir # $tusr # $thom # $tpat" >/tmp/pwd
    tusr="${hdir%:*}"
    thom="${hdir#*:}"
    tpat="${TEXT#$thom}"
    if [ "$TEXT" != "$tpat" ]; then TEXT="~$tusr$tpat"; fi
  done
fi

# verify length to ensure head and tail don't repeat anything, then abridge
[ "$(echo $TEXT|wc -c)" -gt "$c" ] && \
  TEXT=`echo $TEXT|sed -e "s:^.\{$a\}:&///:" -e "s:.\{$b\}$:///&:" -e "s:///.*///:...:"`
#  b=`expr $b + 1` TEXT="`echo $TEXT|head -c$a`...`echo $TEXT|tail -c$b`"

echo $TEXT