content-fix-frontmatter-hashtag.sed

/^tags: .*"#".*$/s/"#","#"/"starred"/g  
/^tags: .*"#".*$/s/"#"/"starred"/g  
/^tags: .*#.*$/s/#//g

Speedrun

find content/blog -type f -name '*.md' -exec sed -i "" -f content-fix-frontmatter-hashtag.sed {} \;