Mini Shell

#!/usr/bin/sh

# Copyright (c) 2004
# Kevin Atkinson
#
# Permission to use, copy, modify, distribute and sell this software
# and its documentation for any purpose is hereby granted without
# fee, provided that the above copyright notice appear in all copies  
# and that both that copyright notice and this permission notice 
# appear in supporting documentation.  Kevin Atkinson makes no
# representations about the suitability of this software for any
# purpose.  It is provided "as is" without express or implied
# warranty.

cmd=`basename "$0"`

warn () 
{
  if test -z "$quiet"; then echo "$cmd: $1" >&2 ; fi
}

error () 
{
  echo "$cmd: $1" >&2
  errors=t
}

zip2 ()
{
  case $1 in
  d) 
    prezip-bin -d "$cmd: $2"
    ;;
  z)
    if test "$sort"
    then
      LC_COLLATE=C sort -u | prezip-bin -z "$cmd: $2"
    else
      prezip-bin -z "$cmd: $2"
    fi
    ;;
  esac
  if test $? -eq 0
  then
    return 0
  else
    errors=t
    return 1
  fi
}

zip ()
{
  if test -e "$3" -a ! "$force"
  then
    error "Output file $3 already exists."
    return 1
  fi
  zip2 $1 "$2: " < "$2" > "$3"
  if test $? -eq 0
  then
    if test -z "$keep"; then rm "$2"; fi
    return 0
  else
    rm "$3"
    return 1
  fi
}

case $cmd in
prezip)   mode=z ;;
preunzip) mode=d ;; 
precat)   mode=d; stdout=t ;;
*)        mode=h ;;
esac

num=0
for p
do
  case $p in
  --*)
    parm=`expr "x$p" : '...\(.*\)'`
    case $parm in
    decompress ) mode=d ;;
    compress   ) mode=z ;;
    keep       ) keep=t ;;
    force      ) force=t ;;
    stdout     ) stdout=t ;;
    sort       ) sort=t ;;
    nocwl      ) nocwl=t ;;
    license    ) mode=L ;;
    version    ) mode=V ;;
    help       ) mode=h ;;
    quiet      ) quiet=t ;;
    *          ) error "invalid option -- $parm";;
    esac
    ;;
  -* ) 
    p=`expr "x$p" : '..\(.*\)'`
    while test "$p"
    do
      parm=`expr "$p" : '\(.\)'`
      p=`expr "$p" : '.\(.*\)'`
      case $parm in
      d ) mode=d ;;
      z ) mode=z ;;
      k ) keep=t ;;
      f ) force=t ;;
      c ) stdout=t ;;
      s ) sort=t ;;
      S ) nocwl=t ;;
      L ) mode=L ;;
      V ) mode=V ;;
      h ) mode=h ;;
      q ) quiet=t ;;
      * ) error "invalid option -- $parm";;
      esac
    done
    ;;
  * )
    num=`expr $num + 1`
    ;;
  esac
done

if test "$errors" 
then
  mode=h
fi

case $mode in
h ) 
  prezip-bin -V
  cat <<EOF

  usage $0 [-dzhLV] [-cfksSq] [file ...]

   -h --help        display help
   -d --decompress  force decompression
   -z --compress    force compression
   -L --license     display software license
   -V --version     display version

   -c --stdout      decompress to standard output
   -f --force       force
   -k --keep        keep input files
   -s --sort        sort and remove duplicates before compressing
   -S --nocwl       do not rename .wl suffix to .cwl (use .wl.pz instead)
   -q --quiet       suppress all warnings

  If invoked as "prezip" the default action is to compress.
             as "preunzip" the default action is to decompress.
             as "precat" the default action is to decompress to stdout.

  If no file names are given then prezip will compress or decompress
  from the standard input to the standard output.  Short flags can be
  combined so that "-c -s" is the same as "-cs".

  Prezip is _not_ a general purpose compressor.  It should only be
  used on sorted word lists or other similar text files.  It will
  likely _increase_ the size of binary data.

EOF
  ;;
L )
  prezip-bin -V
  cat <<EOF

  Copyright (c) 2004
  Kevin Atkinson

  Permission to use, copy, modify, distribute and sell this software
  and its documentation for any purpose is hereby granted without
  fee, provided that the above copyright notice appear in all copies  
  and that both that copyright notice and this permission notice 
  appear in supporting documentation.  Kevin Atkinson makes no
  representations about the suitability of this software for any
  purpose.  It is provided "as is" without express or implied
  warranty.

EOF
  ;;
V ) 
  prezip-bin -V
  ;;
d | z )
if test $num -gt 0
then
  for f
  do
    case $f in
    -* ) ;;
    * )
      if test \( -f "$f" -a ! -L "$f" \) \
              -o \( \( "$stdout" -o "$force" \) -a -L "$f" \)
      then
        if test "$stdout"
        then
          zip2 $mode "$f: " < "$f"
        else
          case $mode in
          d )
            dir=`dirname "$f"`
            file=`basename "$f"`
            base=`basename "$f" .pz`
            base2=`basename "$f" .cwl`
            if test "$file" != "$base"
            then
              out="$dir/$base"
              zip d "$f" "$out"
            elif test "$file" != "$base2"
            then
              out="$dir/$base2.wl"
              zip d "$f" "$out"
            elif test "$force"
            then 
              out="$f.out"
              warn "can't guess original name - using \"$out\""
              zip d "$f" "$out"
            else
              warn "$f does not end in .pz or .cwl - ignored"
            fi
            ;;
          z )
            dir=`dirname "$f"`
            file=`basename "$f"`
            base=`basename "$f" .wl`
            if test "$nocwl" -o "$file" = "$base"
            then
              zip z "$f" "$f.pz"
            else
              zip z "$f" "$dir/$base.cwl"
            fi
            ;;
          esac
        fi
      elif test -e "$f"
      then
        warn "$f is not a regular file - ignored"
      else
        error "$f: No such file"
      fi
      ;;
    esac
  done
else
  case $mode in
  d ) zip2 d ;;
  z ) zip2 z ;;
  esac
fi
;;
esac

if test "$errors" 
then
  exit 1
else
  exit 0
fi