Find the counts of a pattern across files in a folder

count-pattern.sh

#!/bin/sh
usage()
{
        echo -e "Usage: $0 -i <input folder path containing files to search> -j <file name pattern> -p <pattern to search> -e <pattern to exclude from search results> -l <Character to compare for uniqueness> -f <Number of prefix fields to ignore while printing matching lines" \
        "\nExample Usage: ./count-pattern.sh -i /mnt/installation/crx-quickstart/logs -j *log* -p *ERROR* -e 'Non-existant pattern' -l 25 -f 6" 1>&2; exit 1;
}
while getopts i:j:p:e:l:f: option
do
        case "${option}"
        in
                i) SOURCE_FOLDER=${OPTARG};;
                j) FILE_NAME_PATTERN=${OPTARG};;
                p) PATTERN=${OPTARG};;
                e) EXCLUDE_PATTERN=${OPTARG};;
                l) COMPARE_LENGTH=${OPTARG};;
                f) IGNORE_FIELDS=${OPTARG};;
                *) usage;;
        esac
done
for FILE in $SOURCE_FOLDER/$FILE_NAME_PATTERN
do
        OUTPUT=`grep "$PATTERN" $FILE | grep -v "$EXCLUDE_PATTERN" | wc -l`
        if [ "$OUTPUT" -eq "0" ];then
                continue
        fi
        echo $FILE:$OUTPUT
        grep "$PATTERN" $FILE | grep -v "$EXCLUDE_PATTERN" | cut -d ' ' -f $IGNORE_FIELDS- | sort | uniq -c -w $COMPARE_LENGTH
done