#!/bin/bash
# wf2.sh: Crude word frequency analysis on a text file.

# Uses 'xargs' to decompose lines of text into single words.
# Compare this example to the "wf.sh" script later on.


# Check for input file on command-line.
ARGS=1
E_BADARGS=85
E_NOFILE=86

if [ $# -ne "$ARGS" ]
# Correct number of arguments passed to script?
then
  echo "Usage: `basename $0` filename"
  exit $E_BADARGS
fi

if [ ! -f "$1" ]       # Does file exist?
then
  echo "File \"$1\" does not exist."
  exit $E_NOFILE
fi



#####################################################
cat "$1" | xargs -n1 | \
#  List the file, one word per line. 
tr A-Z a-z | \
#  Shift characters to lowercase.
sed -e 's/\.//g'  -e 's/\,//g' -e 's/ /\
/g' | \
#  Filter out periods and commas, and
#+ change space between words to linefeed,
sort | uniq -c | sort -nr
#  Finally remove duplicates, prefix occurrence count
#+ and sort numerically.
#####################################################

#  This does the same job as the "wf.sh" example,
#+ but a bit more ponderously, and it runs more slowly (why?).

exit $?