Spell Checker

#!/bin/bash
# requires apt packages: aspell, aspell-en

RED='\033[0;31m'
GREEN='\033[0;32m'
BLUE='\033[0;36m'
NC='\033[0m' # No Color

MARKDOWN_FILES_CHANGED=`(git diff --cached --name-only || true) | grep .md`

if [ -z "$MARKDOWN_FILES_CHANGED" ]
then
    echo -e "$GREEN>> No markdown file to check $NC"

    exit 0;
fi

echo -e "$BLUE>> Following markdown files were changed in this pull request (commit range: $TRAVIS_COMMIT_RANGE):$NC"
echo "$MARKDOWN_FILES_CHANGED"

# cat all markdown files that changed
TEXT_CONTENT_WITHOUT_METADATA=`cat $(echo "$MARKDOWN_FILES_CHANGED" | sed -E ':a;N;$!ba;s/\n/ /g')`
# extract main content
TEXT_CONTENT_WITHOUT_METADATA=`echo "$TEXT_CONTENT_WITHOUT_METADATA" | sed -n '/## Notes/,/## Link/p'`
# remov md headings
TEXT_CONTENT_WITHOUT_METADATA=`echo "$TEXT_CONTENT_WITHOUT_METADATA" | egrep -v "^#"`
# remove { } attributes
TEXT_CONTENT_WITHOUT_METADATA=`echo "$TEXT_CONTENT_WITHOUT_METADATA" | sed -E 's/\{:([^\}]+)\}//g'`
# remove html
TEXT_CONTENT_WITHOUT_METADATA=`echo "$TEXT_CONTENT_WITHOUT_METADATA" | sed -E 's/<([^<]+)>//g'`
# remove code blocks
TEXT_CONTENT_WITHOUT_METADATA=`echo "$TEXT_CONTENT_WITHOUT_METADATA" | sed  -n '/^\`\`\`/,/^\`\`\`/ !p'`
# remove links
TEXT_CONTENT_WITHOUT_METADATA=`echo "$TEXT_CONTENT_WITHOUT_METADATA" | sed -E 's/http(s)?:\/\/([^ ]+)//g'`

echo -e "$BLUE>> Checking in 'en' (many technical words are in English anyway)...$NC"
MISSPELLED=`echo "$TEXT_CONTENT_WITHOUT_METADATA" | aspell --lang=en --encoding=utf-8 --personal=$HOME/.local/share/aspell/.aspell.en.pws list | sort -u`

NB_MISSPELLED=`echo "$MISSPELLED" | wc -l`

if [ "$NB_MISSPELLED" -gt 0 ]
then
    echo -e "$RED>> Words that might be misspelled, please check:$NC"
    MISSPELLED=`echo "$MISSPELLED" | sed -E ':a;N;$!ba;s/\n/, /g'`
    echo "$MISSPELLED"
else
    echo -e "$GREEN>> $COMMENT $NC"
f