Top 9 Command-Line Download Helpers (aria2, wget, curl Workflows) That Sysadmins Use to Automate Large File Retrieval and Checksum Verification

If you’re a sysadmin or just someone who likes to download things the smart way, you’ve probably spent quality time with the terminal. Forget clicking “Download” in a browser and waiting forever. The command line is your best friend when it comes to fast, automated, and verifiable downloads.

TL;DR

Command-line tools like wget, curl, and aria2 are superheroes for downloading files quickly and securely. They support automation, checksum verification, and can resume stopped downloads. Other helpers like axel and lftp give you even more control. We’re going to show you 9 tools every sysadmin swears by to automate downloads perfectly.

1. wget: The Classic Veteran

wget is an oldie, but a goldie. It’s been around forever and still gets the job done. It’s perfect for downloading files from the internet using HTTP, HTTPS, and FTP. Most Linux systems come with wget pre-installed.

• Resumes broken downloads with -c
• Download entire websites with –mirror
• Supports basic authentication

Example:

wget -c https://example.com/hugefile.iso

2. curl: The Swiss Army Knife

curl is possibly the most versatile download tool. It supports a wide array of protocols including HTTP, FTP, SFTP, and more. Besides downloading, curl can even test APIs and upload files.

• Supports custom headers
• Works well with scripting
• Good for API interaction

Example:

curl -O https://example.com/hugefile.iso

Want to resume a file?

curl -C - -O https://example.com/hugefile.iso

3. aria2: The Fast And Furious Downloader

aria2 is for when you want speed. It lets you download a file from multiple sources simultaneously. Think BitTorrent meets HTTP and FTP. Great for large files!

• Supports metalinks and torrents
• Can split downloads into multiple connections
• Lightweight and scriptable

Example:

aria2c -x 16 https://example.com/hugefile.iso

This uses 16 connections to download the file. Zoom!

4. axel: Lightweight But Speedy

axel is a lightweight command-line tool that also downloads files using multiple connections. It’s simpler than aria2 and perfect for small systems or when you want something fast but not bloated.

• Multi-threaded downloads
• Easy syntax
• Good for scripting

Example:

axel -n 10 https://example.com/hugefile.iso

5. lftp: Beyond Just FTP

Don’t let the name fool you. lftp does more than FTP. It supports HTTP, FTP, and SFTP. It’s a great tool for syncing directories and scripting complex download workflows.

• Supports scripting and automation
• Good for recursive downloads
• Can handle broken or slow FTP servers

Example:

lftp -e "pget -n 5 hugefile.iso; bye" -u user,password sftp://example.com

6. rsync: For syncing like a boss

rsync is a bit different. It’s not a downloader for websites, but ideal for syncing folders and files between servers. You can use SSH for secure transfers. It’s fast, incremental, and incredibly powerful.

• Great for backups
• Only transfers changed parts
• Supports compression over network

Example:

rsync -avz user@host:/remote/folder/ /local/folder/

7. rclone: Cloud Storage Whisperer

rclone is like rsync but for the cloud. It’s perfect for downloading from Google Drive, S3, Dropbox, and many others. It can sync, move, mount, and copy files easily across services.

• Supports over 40 cloud providers
• Password protected config
• Transfers are encrypted

Example:

rclone copy remote:bigdatafile.iso ./localdir/

8. httrack: The Website Cloner

If you ever wanted a full offline copy of a site, this is your tool. httrack basically clones websites by crawling every page, image, and file. Useful for testing or archival purposes.

• Easy mirroring of websites
• Respects robots.txt unless told otherwise
• Works recursively

Example:

httrack https://example.com -O ./webclone

9. sha256sum (and friends): Verify Before You Trust

Once your download is complete, how do you know it’s valid? That’s where checksum tools come in. sha256sum, md5sum, and shasum help you verify the integrity of your downloads.

• Compare downloaded checksums with official ones
• Prevent running corrupted or tampered files
• Scriptable and fast

Example:

sha256sum hugefile.iso

Then compare the output with the checksum provided on the website. If they match, you’re good to go!

Putting It All Together: Automating the Flow

Here’s a little taste of what automation might look like with these tools:

#!/bin/bash
FILE=https://example.com/hugefile.iso
CHECKSUM="ab12cd34..."

# Step 1: Download using aria2
aria2c -x 16 $FILE

# Step 2: Verify checksum
DOWNLOADED_FILE=$(basename $FILE)
if echo "$CHECKSUM  $DOWNLOADED_FILE" | sha256sum -c -; then
    echo "Download and verification successful!"
else
    echo "Checksum does not match!"
    exit 1
fi

You can script similar flows with curl, wget, or any other tool mentioned above.

Bonus Tips

• Use cron jobs to schedule regular downloads.
• Add retries to handle flaky connections.
• Log all actions to files for future auditing.
• Combine with tmux or screen for persistent sessions.

Conclusion

Downloading files from the command line is faster, safer, and more automation-friendly than clicking around in your browser. Whether you’re pulling ISOs overnight, syncing from a cloud drive, or getting the latest patches across servers, there’s a tool here that fits your need.

Learn them, script them, and save yourself hours of manual labor. Your future self will thank you!