Create aria2 input file from all files from a Slack workspace export folder.

slack-files-downloader.sh

#!/bin/bash 
#
# This script will browse a Slack export folder and generate an aria2 input file to download all files to an "attachments" folder in each channel folder.
# 
# HOW TO:
# 1. As a Workspace admin, download an export of your Slack history (https://www.slack.com/services/export) 
# 2. Make sure you have jq installed (https://stedolan.github.io/jq/)
# 3. Place this file at the root of your Slack export folder, next to channels.json
# 4. Run `bash slack-downloader.sh` in your terminal
#
output_file=file_download_list

: > "$output_file" 

for channel in $(cat channels.json | jq -rc '.[].name'); do
    printf "\n============================================\nLooking into #$channel...\n============================================\n"
    jq -r -c '.[].files | select(length > 0) | .[] | select(.is_external == false) |
        .url_private_download + "\n" +
            "    dir='$channel'/attachments\n" +
            "    out=" + .id + "-" + .name' $channel/*.json >> "$output_file"
done