Decompress multiple gzipped files into one file

E.g. I have multiple old Apache access logs (which are compressed with gzip) and I want to extract them all into one large log.

You can use cat to combine all the gzipped files into one file, then decompress the one large file.

cat *.gz > all.gz
gzip -d all.gz


Can’t connect to wireless networks in new versions of Debian/Ubuntu

Symptom: select a network and type network passphrase. The wifi indicator will blink, spin, whatever to show that it’s connecting. It will keep doing that for a while, then say “Disconnected”

Edit the file


Then add this to the bottom of that file:


Save file, run

sudo service network-manager restart

Then it will work.

Reset OpenVPN Access Server

If your Access Server isn’t working (mine stopped listening on all ports, web interface wasn’t accessible), run the initialization script to set it up from scratch.


Log into the console as root and run the following command:
/usr/local/openvpn_as/bin/ovpn-init –force

Certbot Let’s Encrypt Apache

My server had a Let’s Encrypt certificate configured on the default site. When I added a virtual host and tried running the regular letsencrypt tool on the new vhost site, it failed with this error:

Failed authorization procedure. (tls-sni-01): urn:acme:error:connection :: The server could not connect to the client to verify the domain :: Failed to connect to :443 for TLS-SNI-01 challenge

I suspect it was because the default certificate (for the main domain) was being served for the new vhost on a different domain.

So, run certbot instead:

root@vps:~# wget
root@vps:~# chmod +x certbot-auto
root@vps:~# ./certbot-auto –apache -d

It had to download and install some dependency packages, then asked whether to allow HTTP and HTTPS access to your site or redirect HTTP requests to HTTPS.

It creates the site’s SSL configuration file, adds the certificate files to that config, and edits the old file to rewrite HTTP URLs to HTTPS (if you asked for that)


Apache create virtual host

If you want to create a site on a different subdomain or domain, for example.

Create a directory like this to hold the site files (and drop some files in there):

sudo mkdir -p /var/www/

Create the config file for the site by copying the default:

sudo cp /etc/apache2/sites-available/000-default.conf /etc/apache2/sites-available/

Edit the new config file and change the ServerName and DocumentRoot lines to match the new site’s parameters.

Lastly, enable the new site config file and reload the server.

service apache2 reload

Use ThinkPad laptop fingerprint reader in Ubuntu/Linux

This might work on other brands and models.

For Ubuntu 16.04 or greater:

sudo apt install libpam-fprintd

Run fprintd-enroll to set up (enroll) the fingerprint.

This will automatically make your login screen require a finger swipe instead of a password.

It will also use a fingerprint in the terminal:

chris@chris-T430:~$ sudo su
Swipe your finger across the fingerprint reader

Linux locale errors

such as “mosh-server needs a UTF-8 native locale to run.” and it will specify the one it is looking for, such as en_US

on the server, run dpkg-reconfigure locales, select the one being requested, and then set the default locale as the one you created (I think. I did that and it worked, but who knows if it’s actually required)

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