$ wget https://www.openssl.org
...
ERROR: cannot verify www.openssl.org's certificate, issued by '/C=US/O=Let\'s Encrypt/CN=R3':
Issued certificate has expired.
$ curl https://www.openssl.org
curl: (60) SSL certificate problem: certificate has expired
$ sudo dpkg-reconfigure ca-certificates
Problem: when install an npm package in global.
you@computer:~/path $ npm install -g (package)
npm WARN checkPermissions Missing write access to /usr/local/lib
npm ERR! code EACCES
npm ERR! syscall access
npm ERR! path /usr/local/lib
npm ERR! errno -13
npm ERR! Error: EACCES: permission denied, access '/usr/local/lib'
npm ERR! { [Error: EACCES: permission denied, access '/usr/local/lib']
npm ERR! stack:
npm ERR! 'Error: EACCES: permission denied, access \'/usr/local/lib\'',
npm ERR! errno: -13,
npm ERR! code: 'EACCES',
npm ERR! syscall: 'access',
npm ERR! path: '/usr/local/lib' }
...
Solution: configure npm to use a different directory for global installation.
1.Create a directory for global installation:
$ mkdir ~/.npm-global
2.Configure npm to use the new directory path:
npm config set prefix '~/.npm-global'
3.Add the directory to $PATH in the ~/.profile:
echo 'export PATH="~/.npm-global/bin:$PATH"' >> ~/.profile
4.Update your system variables:
source ~/.profile
Test: Download a package globally without using sudo.
npm install -g (something)
If it still shows permission error (mac os), run:
sudo chown -R $USER ~/.npm-global
pi@raspberrypi:~ $ sudo systemctl start docker.service
Job for docker.service failed because the control process exited with error code.
See "systemctl status docker.service" and "journalctl -xe" for details.
pi@raspberrypi:~ $ sudo dockerd
INFO[...] Starting up
...
...
failed to start daemon: error initializing graphdriver: /var/lib/docker contains several valid graphdrivers: overlay2, devicemapper; Please cleanup or explicitly choose storage driver (-s )
We found the problem. It looks like it could not decide it's own storage driver. There are 'overlay2' and 'devicemapper' to choose from.
pi@raspberrypi:~ $ sudo dockerd -s overlay2
OR use a more readable version: "--storage-driver=overlay2".
pi@raspberrypi:~ $ sudo dockerd --storage-driver=overlay2
INFO[...] Starting up
...
...
INFO[...] Daemon has completed initialization
INFO[...] API listen on /var/run/docker.sock
Now it works.
pi@raspberrypi:~ $ sudo vi /lib/systemd/system/docker.service
Look for a line with "ExecStart" append "--storage-driver=overlay2" to the line, so it looks like this:
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock --storage-driver=overlay2
pi@raspberrypi:~ $ sudo systemctl daemon-reload
pi@raspberrypi:~ $ sudo systemctl start docker.service
| Type | Description | Pros. | Cons. |
| UTP | Unshielded Twisted Pairs. No foil or braided shielding. |
|
|
| STP | Shielded Twisted Pairs. Has braided shielding to reduce noise and improve connection quality. |
|
|
| FTP | Foiled Twisted Pairs. Has foil shielding to reduce noise and improve connection quality. |
|
|
| Category | Shielding | Max Transmission Speed (at 100 meters) |
Max Bandwidth | Note |
| Cat 5 | UTP | 100 Mbps | 100 MHz | Obsolete. |
| Cat 5e | UTP, F/UTP, U/FTP | 1 Gbps | 100 MHz | Common cheap cable. e = enhanced. |
| Cat 6 | UTP, F/UTP, U/FTP | 1 Gbps | 250 MHz | 10 Gbps up to 55 meters. |
| Cat 6a | UTP, F/UTP, U/FTP, S/FTP | 10 Gbps | 500 MHz | a = augmented. |
| Cat 7 | S/FTP, F/FTP | 10 Gbps | 600 MHz | Not TIA/EIA standard. GG45 connector |
| Cat 7a | S/FTP, F/FTP | 10 Gbps | 1,000Mhz | Not TIA/EIA standard. 100 Gbps up to 15 meters. 40 Gbps up to 50 meters. |
| Cat 8/8.1 | F/UTP, U/FTP | 10 Gbps | 2,000Mhz | For data center. Short cable, less than 30-36m. 40 Gbps up to 30m. RJ45 connector. |
| Cat 8.2 | S/FTP, F/FTP | 10 Gbps | 2,000Mhz | Same as 8.1. GG45 connector. |