Polish letters to UTF-8 translator

sed_pl.sh

#!/bin/bash
##################################################################
## Polish letters to UTF-8 translator
##
## www.PiotrNowicki.com
##################################################################
##
## The purpose of this script is to translate polish letters (with 
## diacritical marks) to appropriate unicode characters. 
##
## Some files need to be encoded using standards that doesn't 
## allow polish letters (like ISO-8859-1 / Java Properties files.)
##
## Requires: BASH 4
##
## Usage: sed_pl.sh FILE
## Input: file to be transformed
## Output: transformed file printed to stdout
##
#################################################################

# We accept only one argument - input file to be transformed
if [ $# -ne 1 ]; then
    echo 'Usage: sed_pl.sh FILE'
	exit 1;
fi

INPUT=$1

if [ ! -f "$INPUT" ]; then
    echo "File '$INPUT' cannot be found"
	exit 1;
fi

# We use BASH 4.0 associate arrays
declare -A SWAPS

# Define what characters we are translating to what codes
SWAPS=( 
['ą']='\\u0105'
['Ą']='\\u0104'
['ć']='\\u0107'
['Ć']='\\u0106'
['ę']='\\u0119'
['Ę']='\\u0118'
['ł']='\\u0142'
['Ł']='\\u0141'
['ń']='\\u0144'
['Ń']='\\u0143'
['ó']='\\u00F3'
['Ó']='\\u00D3'
['ś']='\\u015B'
['Ś']='\\u015A'
['ż']='\\u017C'
['Ż']='\\u017B'
['ź']='\\u017A'
['Ź']='\\u0179'
)

CMD="sed"

# We create sed translation script in this loop
for KEY in "${!SWAPS[@]}"; do
	VALUE=${SWAPS["$KEY"]}

	CMD="$CMD -e s/$KEY/$VALUE/g"
done

# For debugging purposes
#echo "$CMD"

# Print result of the transformation to stdout
$CMD "$INPUT"