#!/bin/bash
# wf.sh: Crude word frequency analysis on a text file.
# This is a more efficient version of the "wf2.sh" script.
# Check for input file on command line.
ARGS=1
E_BADARGS=65
E_NOFILE=66
if [ $# -ne "$ARGS" ] # Correct number of arguments passed to script?
then
echo "Usage: `basename $0` filename"
exit $E_BADARGS
fi
if [ ! -f "$1" ] # Check if file exists.
then
echo "File \"$1\" does not exist."
exit $E_NOFILE
fi
########################################################
# main ()
sed -e 's/\.//g' -e 's/\,//g' -e 's/ /\
/g' "$1" | tr 'A-Z' 'a-z' | sort | uniq -c | sort -nr
# =========================
# Frequency of occurrence
# Filter out periods and commas, and
#+ change space between words to linefeed,
#+ then shift characters to lowercase, and
#+ finally prefix occurrence count and sort numerically.
########################################################
# Exercises:
# ---------
# 1) Add 'sed' commands to filter out other punctuation,
#+ such as semicolons.
# 2) Modify to also filter out multiple spaces and other whitespace.
# 3) Add a secondary sort key, so that instances of equal occurrence
#+ are sorted alphabetically.
exit 0
