Autosave: 2025-04-05 10:32:40

neuron/9445c5fd-135c-4b0b-a70c-7a6fd45d9d58/Certbot.md

@@ -0,0 +1,25 @@
+---
+tags: [server-management, procedural]
+created: Wednesday, April 02, 2025
+---
+
+# Certbot
+
+## Generate certificates for new subdomain
+
+```sh
+sudo certbot certonly --standalone -d rootdomain.net -d subdomainA.rootdomain.net -d subdomainB.rootdomain.net
+```
+
+## List certificates
+
+```sh
+sudo certbot certificates
+```
+
+## Delete a certifcate
+
+```sh
+sudo cerbot delete --certname rootdomain.net
+
+```

neuron/9445c5fd-135c-4b0b-a70c-7a6fd45d9d58/Code_Craft_The_Practice_Of_Writing_Excellent_Code.md

@@ -46,6 +46,8 @@ initialization; a nearby declaration makes it obvious.
 This can be achieved with good naming alone if you are clever about it. It
 doesn't necessarily require automated tools or excessive commentary.
 
+> Don't document bad code - rewrite it. (Kernighan et al.)
+
 ### Scope
 
 - With smaller, more specific scope we can name things in a more intuitive and
@@ -72,3 +74,37 @@ doesn't necessarily require automated tools or excessive commentary.
   description of how the code works. You should instead focus on describing why
   something is written the way it is or what the next block of statements
   ultimately achieves.
+
+## Error handling
+
+- Handling errors well is challenging! It is not easy to write good error
+  handling that doesn’t twist and warp the underlying program logic.
+
+- Try to throw errors close enough to the source to prevent obscure and
+  out-of-context error handling _while_ being far enough away not to cloud
+  normal code with roundabout paths.
+
+  - _This is something I struggle with. The error is caught later than when it
+    occurs and then all I have is a generic catch-all error that is hard to make
+    sense of._
+
+### Close to source - benefits
+
+- Managing each error near its source means that control passes through less
+  code in an invalid state. By handling an error near to its cause, you retain
+  important contextual information, making the error-handling code clearer.
+
+### As late as possible - benefits
+
+- This recognizes that code detecting an error rarely knows what to do about it.
+  It often depends on the context in which it is used. You can pass an exception
+  through each level until you know how to deal with the error.
+
+### Errors to check for
+
+- Function/method parameters
+  - Ensure you have been given correct and consistent input. Consider using
+    assertions for this.
+  - Check that invariants are satisfied at interesting points in execution
+  - Check all values from external sources for validity before you use them
+  - Check the return status of all system and other subordinate function calls.

neuron/9445c5fd-135c-4b0b-a70c-7a6fd45d9d58/Docker_cleanup.md

@@ -5,6 +5,12 @@ created: Thursday, March 27, 2025
 
 # Docker cleanup
 
+## Generic clean-up: free as many bytes as possible
+
+```sh
+sudo docker system prune -a
+```
+
 ## Check Docker storage usage
 
 ```sh

neuron/9445c5fd-135c-4b0b-a70c-7a6fd45d9d58/index.md

@@ -13,17 +13,18 @@ computer science.
 
 <a href="https://thomasabishop.github.io/eolas/tags">View tags</a>
  
-**Build ID:** 6d4cfb04-1e87-477a-91e9-34c360bfb8ad
+**Build ID:** 9445c5fd-135c-4b0b-a70c-7a6fd45d9d58
 
-**Published:** Thu 27 Mar 2025 19:06:00
+**Published:** Sat 05 Apr 2025 10:32:35
 
 ### Recent edits 
 
+- [[Code_Craft_The_Practice_Of_Writing_Excellent_Code]] 
 - [[Docker_cleanup]] 
+- [[Certbot]] 
 - [[d212acdb_from_free-software_to_open_source]] 
 - [[c8820974_Tor_prioritising_uptake]] 
 - [[What_can_the_ISP_see]] 
-- [[Code_Craft_The_Practice_Of_Writing_Excellent_Code]] 
 - [[Constructing paths in Python]] 
 - [[File_operations_in_Python]] 
 - [[Using a context manager in Python]] 
@@ -38,10 +39,9 @@ computer science.
 - [[How_tunneling_works_with_VPNs]] 
 - [[Network_tunnels]] 
 - [[Capturing_program_error_in_Bash]] 
-- [[Check_if_value_null_in_Bash]] 
 
 
-### All notes (547) 
+### All notes (548) 
 
 - [[0716531c_rewilding_the_internet]] 
 - [[241fe1a3_the_Web_versus_modem_BBSs]] 
@@ -123,6 +123,7 @@ computer science.
 - [[Capturing_user_input_in_Bash]] 
 - [[Case_statements_in_Bash]] 
 - [[Cells_and_batteries]] 
+- [[Certbot]] 
 - [[Certificate_authorities]] 
 - [[Check_if_value_null_in_Bash]] 
 - [[Cherry_picking]] 

neuron/9445c5fd-135c-4b0b-a70c-7a6fd45d9d58/tags.md

@@ -861,6 +861,7 @@ unlisted: true
 - [[Appending_to_files_in_Python]] 
 - [[AWS_CLI]] 
 - [[Bluetooth]] 
+- [[Certbot]] 
 - [[Compile_from_source]] 
 - [[Compile_Python_app_to_single_executable]] 
 - [[Create_timed_systemd_job]] 
@@ -1046,6 +1047,7 @@ unlisted: true
 - [[Bash_store_status_of_command_execution]] 
 ### server-management 
 
+- [[Certbot]] 
 - [[Certificate_authorities]] 
 - [[Disable_non-root_ssh_access]] 
 - [[Firewalls]] 

zk/Certbot.md

@@ -0,0 +1,25 @@
+---
+tags: [server-management, procedural]
+created: Wednesday, April 02, 2025
+---
+
+# Certbot
+
+## Generate certificates for new subdomain
+
+```sh
+sudo certbot certonly --standalone -d rootdomain.net -d subdomainA.rootdomain.net -d subdomainB.rootdomain.net
+```
+
+## List certificates
+
+```sh
+sudo certbot certificates
+```
+
+## Delete a certifcate
+
+```sh
+sudo cerbot delete --certname rootdomain.net
+
+```

zk/Code_Craft_The_Practice_Of_Writing_Excellent_Code.md

@@ -46,6 +46,8 @@ initialization; a nearby declaration makes it obvious.
 This can be achieved with good naming alone if you are clever about it. It
 doesn't necessarily require automated tools or excessive commentary.
 
+> Don't document bad code - rewrite it. (Kernighan et al.)
+
 ### Scope
 
 - With smaller, more specific scope we can name things in a more intuitive and
@@ -72,3 +74,37 @@ doesn't necessarily require automated tools or excessive commentary.
   description of how the code works. You should instead focus on describing why
   something is written the way it is or what the next block of statements
   ultimately achieves.
+
+## Error handling
+
+- Handling errors well is challenging! It is not easy to write good error
+  handling that doesn’t twist and warp the underlying program logic.
+
+- Try to throw errors close enough to the source to prevent obscure and
+  out-of-context error handling _while_ being far enough away not to cloud
+  normal code with roundabout paths.
+
+  - _This is something I struggle with. The error is caught later than when it
+    occurs and then all I have is a generic catch-all error that is hard to make
+    sense of._
+
+### Close to source - benefits
+
+- Managing each error near its source means that control passes through less
+  code in an invalid state. By handling an error near to its cause, you retain
+  important contextual information, making the error-handling code clearer.
+
+### As late as possible - benefits
+
+- This recognizes that code detecting an error rarely knows what to do about it.
+  It often depends on the context in which it is used. You can pass an exception
+  through each level until you know how to deal with the error.
+
+### Errors to check for
+
+- Function/method parameters
+  - Ensure you have been given correct and consistent input. Consider using
+    assertions for this.
+  - Check that invariants are satisfied at interesting points in execution
+  - Check all values from external sources for validity before you use them
+  - Check the return status of all system and other subordinate function calls.

zk/Docker_cleanup.md

@@ -5,6 +5,12 @@ created: Thursday, March 27, 2025
 
 # Docker cleanup
 
+## Generic clean-up: free as many bytes as possible
+
+```sh
+sudo docker system prune -a
+```
+
 ## Check Docker storage usage
 
 ```sh