Written 30 Aug 2026. This is a how-to, not a product card.

Shrink one file

After SSH works, shrink one file with gzip so a copy is smaller. You don't need a zip app for this.

A copy is smaller if you shrink the file first. Tonight you shrink one file: gzip. Gzip shrinks one file. Use -k so the original stays. You are still only practicing in home on the computer. It does not need a zip app for this one job.

Skip until SSH already works

SSH from the couch should already get you a prompt. If a folder packed is what you want, that is pack files into one archive. If a zip a laptop can open is what you want, that is pack files into a zip a laptop can open. Skip shrinking /etc or a disk.

What this is

gzip shrinks one file. You type gzip -k ~/shrink-me.txt. -k keeps the original. A .gz file appears next to it. gzip -l lists size. gzip -cd unpacks to the screen or a redirect. It is not tar. Tar packs a folder. It is not zip. Zip is a different archive a laptop often opens.

Shrink a practice file in home

SSH in. Make sure home is where you sit:

pwd

You want a path that ends in your login name. If not:

cd ~

Make a tiny practice file:

yes 'hello' | head -n 40 > ~/shrink-me.txt

ls -lh ~/shrink-me.txt

Shrink it, keep the original:

gzip -k ~/shrink-me.txt

ls -lh ~/shrink-me.txt ~/shrink-me.txt.gz

List the shrink:

gzip -l ~/shrink-me.txt.gz

Unpack into a throwaway folder:

mkdir -p ~/unpack-gz

gzip -cd ~/shrink-me.txt.gz > ~/unpack-gz/shrink-me.txt

ls -lh ~/unpack-gz/shrink-me.txt

That is enough for tonight. Practice only in home.

Debian and Ubuntu usually already have gzip. Don't make apt the job. If gzip is missing:

sudo apt install gzip

Then stop. That install is not the lesson.

When you are done, throw the practice files away. Careful delete only. That is delete a file carefully. Skip rm -rf.

rm -i ~/shrink-me.txt ~/shrink-me.txt.gz

Then the unpack copy:

rm -i ~/unpack-gz/shrink-me.txt

Useful extras, still home only

Optional facts:

stat ~/shrink-me.txt.gz

Optional: verbose keep:

gzip -kv ~/shrink-me.txt

Skip shrinking /etc, whole disks, or files you care about. Tonight: a practice file in home.

What this is not

This is not tar. That is pack files into one archive. It is not zip. That is pack files into a zip a laptop can open. It is not xargs. That is run one command per line. It is not a fingerprint. That is check a file fingerprint. It is not opening SSH to the internet. That is keep the computer on the house network. Don't forward port 22.

What next

Need a folder packed? Pack files into one archive. Need one command per line? Run one command per line. Need a fingerprint? Check a file fingerprint. Keep SSH on the house network: keep the computer on the house network. Don't forward port 22.

Skip

Skip if SSH still fails. Finish SSH from the couch first.
Skip shrinking /etc, whole disks, or files you care about. Tonight: a practice file in home.
Skip tar, zip, and xargs as tonight's job. Those pages already exist.
Skip gzip without -k on a file you still want. Keep the original.
Skip files under /etc, SSH folders, or paths you don't own. Practice only in home.
Skip rm -rf. Careful delete only: delete a file carefully.
Skip opening SSH to the internet so you can do this from a coffee shop. That is keep the computer on the house network. Don't forward port 22.

Sources

Debian: gzip. Ubuntu: gzip. GNU gzip. Official pages only. For the login, see SSH from the couch. For a folder packed, see pack files into one archive.

Also on this topic

SSH from the couchType commands on the computer from your laptop, on the house network. Password login first. Don't open this to the internet. Pack files into one archiveAfter SSH works, pack files into one archive with tar so you can copy one file instead of a folder. You don't need a zip app for this. See file size, date, and permissionsAfter SSH works, see file size, date, and permissions with stat. You don't need extra software for this. Check a file fingerprintAfter SSH works, check a file with sha256sum so you know it still matches the fingerprint you expected. You don't need a download manager for this. Download a file onto the computerAfter SSH works, pull one file from a web address with curl. You don't need a browser on the computer for this. Copy a file to the computer from your laptopAfter SSH works, use scp to move one file without a USB stick. You don't need a NAS for this. Copy a file without leaving the computerAfter SSH works, copy a file with cp so you can edit a spare without wrecking the original. You don't need a NAS for this. Delete a file carefullyAfter SSH works, delete one file with rm -i. Ask first. Skip rm -rf. You don't need a NAS for this. Run one command per lineAfter SSH works, run one command once per line with xargs so a list drives many short jobs. You don't need a scripting app for this. Turn off password login once the key worksAfter the laptop key login is boring, tell SSH to stop accepting the password. The key is how you get in. A keyboard on the computer is the backup now. Keep the computer on the house networkSSH and Pi-hole belong on the house network. Skip this if you never opened the router settings. Don't forward port 22.