Renames files with specific extensions to contain only snake-case lowercase titles

rename.sh

#!/usr/bin/bash

# Check if they passed an arugment for which extensions to convert
if [[ $# -eq 0 ]]; then
    exts="mkv"
else
    exts="$@"
fi

for ext in $exts; do
    for file in *.$ext; do
        if [[ -f $file ]]; then
            new_name=$(echo "$file" | sed -E \
                -e 's/.*/\L&/'                          `# convert to lowercase`\
                -e 's/\[[^]]+\]//g'                     `# remove anything inside []`\
                -e 's/\([^)]+\)//g'                     `# remove anything inside ()`\
                -e 's/^[[:blank:]]+//'                  `# remove leading whitespace`\
                -e 's/[[:blank:]]+\.'"$ext/.$ext/"      `# remove trailing whitespace`\
                -e 's/[[:blank:]]+/-/g'                 `# convert whitespace to '-'`\
                -e 's/-+/-/g'                           `# replace multiple --- with single -`\
            )

            mv "$file" "$new_name"
        fi
    done
done