#!/bin/sh
##############################################################################
# Rename 0.1 (beta)
##############################################################################
# Author: Adam Carheden, 4/14/2000
##############################################################################
# Licence: GNU GPL
# Copy, modify, sell, etc., so long as others can do the same.
##############################################################################
# Description:
# Renames files from STDIN based on tr character translation
# Default behavior is to rename files by translating upper case characters to
# lower case characters
##############################################################################
# Examples: 
# - Rename all files in the current directory to all lowercase letters
#   ls | rename
# - Rename all files in the current directory to all uppercase letters
#   ls | rename -u
# - Test the script (Does everything but call mv)
#   ls | rename -t
# - Rename only files that start with an upper case character from A to C
#   ls | rename --regexp '^[A-C].*'
# - Rename files so that all occurences of 'A' are replaced with 'B'
#   ls | rename --chars A B
##############################################################################

# Defaults
myName="$0"
testOnly=''
verbose=''
regexp='^\.\.\?$' # Refuse to rename std dir pointers
grepNeg='-v'
usage="Usage: $0
-h | --help)           Print this message and exit
-v | --verbose)        Verbose output
-c | --chars FROM TO)  Rename based on FROM and TO (see man tr)
-t | --test)           Test only, skip actual renaming
-e | --rexexp REGEXP)  Only rename files if the match the regular expression
-u | --uppercase)      Translate to all uppercase"
from='[:upper:]'
to='[:lower:]'

# Get Arguments
while [ $1 ]
do
  case $1 in
    --help|-h)
      echo -e "${usage}"
      exit 0
      ;;
    --verbose|-v)
      verbose=$1
      shift
      ;;
    --chars|-c)
      shift
      from="$1"
      shift
      to="$1"
      shift
      ;;
    --test|-t)
      testOnly=$1
      shift
      ;;
    --regexp|-e)
      grepNeg=''
      shift
      regexp=$1
      shift
      ;;
    --uppercase|-u)
      from='[:lower:]'
      to='[:upper:]'
      shift
      ;;
    *)
      echo -e "${usage}"
      exit 1
      ;;
  esac
done


# Make sure we have translation operators and a regexp
if [ -z "${from}" ]; then
  echo -e "${usage}"
  echo "FROM empty" 1>&2
  exit 1
fi
if [ -z "${to}" ]; then
  echo -e "${usage}"
  echo "TO empty" 1>&2
  exit 1
fi
if [ -z "${regexp}" ]; then
  echo -e "${usage}"
  echo "REGEXP empty" 1>&2
  exit 1
fi


# Read lines and rename 
read nextFile
more=`echo $?`
while [ "${more}" -eq 0 ]; do

  # Test that the file should be included
  if [ `echo -n "${nextFile}" | grep ${grepNeg} -q -e "${regexp}"; echo $?` -eq 0 ]; then 
    
    # Test that file exists
    if [ -r "${nextFile}" ]; then

      # Get the new name
      newName=`echo -n "${nextFile}" | tr ${from} ${to}`

      # Text for duplicate file name
      if [ "${nextFile}" != "${newName}" ]; then 

        # Make sure the target file doesn't exist
        if [ -r "${newName}" ]; then
          echo "${myName}: A file called '${newName}' already exists, Skipping..." 1>&2
        else
          # Rename the file
          if [ -n "${verbose}" ]; then
            echo "Renaming '${nextFile}' to '${newName}'"
          fi
          if [ -z "${testOnly}" ]; then
            if [ `mv "${nextFile}" "${newName}"; echo $?` -gt 0 ]; then
              echo "${myName}: Error renaming '${nextFile}' to '${newName}'" 1>&2
            fi
          fi
        fi
      else 
        # Report duplicate file name error
        if [ -n "${verbose}" ]; then
          echo "'${newName}' = '${nextFile}', Skipping..."
        fi
      fi
    else
      echo "${myName}: '${nextFile}' does not exist.  Skipping..." 1>&2
    fi
  else
    echo "${myName}: '${nextFile}' doesn't match criteria, Skipping..." 1>&2
  fi

  # Get the next file
  read nextFile
  more=`echo $?`

done

# Indicate testing
if [ -n "${test}" ]; then
  if [ -n "${verbose}" ]; then
    echo "Testing only, file names not modified."
  fi
fi

exit 0