tari - tar "in-place" - Remove duplicates when operating on tar archives

tari.bash

# All my gist code is licensed under the terms of the MIT license.

# Video demo: https://www.youtube.com/watch?v=IyzNz1uPEGg

# deleteAllButMostRecentInTar
# source: https://stackoverflow.com/a/71666950/21567639
function deleteAllButMostRecentInTar()
{
    local archive=$1
    local filesToDelete=$(mktemp)
    local shouldPrintMessage=true

    while true; do
        command tar --list --file "$archive" | sort | uniq -c |
            command sed -n -E '/^[ \t]*1 /d; s|^[ \t]*[0-9]+ ||p' >| "$filesToDelete"
        if [[ -s "$filesToDelete" ]]; then
            if [[ $shouldPrintMessage == true ]]; then
                echo "Found files in archive with multiple versions:"
                cat -- "$filesToDelete"
                shouldPrintMessage=false
                echo "Deleting all but most recent version..."
            fi
            local fileCount=$( cat -- "$filesToDelete" | wc -l )
            tar --delete --occurrence=1 --files-from="$filesToDelete" \
                --file "$archive"
        else
            break
        fi
    done
    if [[ -s "$filesToDelete" ]]; then
        echo "Done."
    fi
    rm -- "$filesToDelete" >/dev/null 2>&1
}

# tar "in-place"
# - an inconvenient feature of tar is that it never overwrites members with the
#   same name, meaning that operations like --append and --update will not
#   replace an existing member with a file of the same name.
# - tar "in-place" is a wrapper around tar that calls
#   deleteAllButMostRecentInTar after every tar operation
function tari () {
  tar "$@"

  # First we must figure out the archive name. Possible formats are:
  # -XXXf <archive>
  # --file=<archive>
  # Note: Old-style tar option (tar cf <archive>) is not supported because it
  # is bonkers.
  local archive_name
  if [[ "$@" =~ -[a-zA-Z0-9]*f[[:space:]]+([^[:space:]]+) ]]; then
    archive_name="${BASH_REMATCH[1]}"
  elif [[ "$@" =~ --file=([^[:space:]]+) ]]; then
    archive_name="${BASH_REMATCH[1]}"
  fi

  # If the archive is compressed, do nothing. (the tar operations that modify
  # archives don't work on compressed archives)
  if [[ "$archive_name" =~ \.(gz|bz2|xz|Z|zst)$ ]]; then
    return
  fi

  if [[ -n "$archive_name" ]]; then
    deleteAllButMostRecentInTar "$archive_name"
  fi
}