Add notes.

2024-02-02 07:48:14 -07:00 · 2024-02-02 07:48:14 -07:00 · 413d48c4d1
parent 7e28ba2efd
commit 413d48c4d1
5 changed files with 113 additions and 9 deletions
--- a/notes/.obsidian/plugins/obsidian-to-anki-plugin/data.json
+++ b/notes/.obsidian/plugins/obsidian-to-anki-plugin/data.json
@ -64,15 +64,17 @@
    "daily/2024-01-31.md": "72e343cef8d56e169cac7b360a88fcf0",
    "posix/index.md": "f7b1ae55f8f5e8f50f89738b1aca9111",
    "posix/signals.md": "2120ddd933fc0d57abb93c33f639afd8",
-    "gawk.md": "4517acfbf4e186e8cc66a9002fbad73f",
+    "gawk.md": "c79a09e1772da1d4f2cd296b7370ecab",
    "bash/index.md": "3b5296277f095acdf16655adcdf524af",
-    "bash/shebang.md": "ad178efeb4a05190b80b5df108c175c7",
+    "bash/shebang.md": "9006547710f9a079a3666169fbeda7aa",
    "bash/robustness.md": "de97cd77aae047b5eea27440b43c9c42",
-    "journal/2024-02-01.md": "f4cc061bfc8e41ce15ae9a354c65ffe9",
+    "journal/2024-02-01.md": "3aa232387d2dc662384976fd116888eb",
    "journal/2024-01-31.md": "7c7fbfccabc316f9e676826bf8dfe970",
    "bash/quoting.md": "b1d8869a91001f8b22f0cdc54d806f61",
    "nix/callPackage.md": "5ef6bc5d1a549c55d43ebb4d48c64427",
-    "nix/index.md": "dd5ddd19e95d9bdbe020c68974d77a33"
+    "nix/index.md": "dd5ddd19e95d9bdbe020c68974d77a33",
+    "journal/2024-02-02.md": "0df6266a5f347124df5ac795bcff51a2",
+    "bash/prompts.md": "64bd3cd3c2feb9edb68ad8dc5ba65a35"
  },
  "fields_dict": {
    "Basic": [
--- a/notes/bash/prompts.md
+++ b/notes/bash/prompts.md
@ -0,0 +1,45 @@
+---
+title: Prompts
+TARGET DECK: Obsidian::STEM
+FILE TAGS: bash
+tags:
+  - bash
+---
+
+## Overview
+
+According to Robbins a POSIX-compliant shell (like Bash) generally has the primary and secondary prompts denoted with `$` and `>` respectively.
+
+%%ANKI
+Basic
+What symbol is usually used to denote the primary prompt?
+Back: `$$`
+Reference:  Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
+<!--ID: 1706882670149-->
+END%%
+
+%%ANKI
+Basic
+What symbol is usually used to denote the secondary prompt?
+Back: `>`
+Reference:  Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
+<!--ID: 1706882670158-->
+END%%
+
+Paths supplied to commands are typically "sanitized" by prefixing the path name with `./`. This is mentioned in a few different places:
+
+* `find -execdir` performs this prefixing automatically on all found files.
+* `awk` ambiguously interprets a file named e.g. `count=1` as variable assignment. Should write `$ awk -f program.awk ./count=1`.
+
+%%ANKI
+Basic
+What methodology is commonly used to "sanitize" paths supplied as command-line arguments?
+Back: Prefixing the paths with `./`.
+Reference: Cooper, Mendel. “Advanced Bash-Scripting Guide,” n.d., 916.
+<!--ID: 1706885111460-->
+END%%
+
+## References
+
+* Cooper, Mendel. “Advanced Bash-Scripting Guide,” n.d., 916.
+* Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
--- a/notes/bash/shebang.md
+++ b/notes/bash/shebang.md
@ -8,7 +8,7 @@ tags:

 ## Overview

-The shebang (also writting shabang or sha-bang) is a magic character at the start of a script indicating what command should be run when invoking the script directly. It always begins with ASCII characters `#!`.[^mendel]
+The shebang (also writting shabang or sha-bang) is a magic character at the start of a script indicating what command should be run when invoking the script directly. It always begins with ASCII characters `#!`.

 %%ANKI
 Basic
--- a/notes/gawk.md
+++ b/notes/gawk.md
@ -40,7 +40,7 @@ END%%

 Robbins suggests executing command `set +H` on [[bash]] startup to disable [[C]] shell-style command history.

-## Usage
+## Structure

 `awk` applies actions to lines matching specified patterns. In this way `awk` is said to be data-driven - we specify the lines `awk` should act on and `awk` is responsible for finding and acting on them. Instructions are provided via a **program**.

@ -88,7 +88,7 @@ Basic
 Write the `awk` command that searches file `mail-list` for string `li`.
 Back:
 ```bash
-$ awk '/li/ { print }' mail-list
+$ awk '/li/' mail-list
 ```
 Reference: Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
 <!--ID: 1706819150999-->
@ -141,7 +141,7 @@ END%%

 %%ANKI
 Basic
-What is the `BEGIN` pattern?
+How is the `BEGIN` pattern interpreted?
 Back: Code associated with it executes before any input is read.
 Reference: Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
 <!--ID: 1706823790236-->
@ -149,7 +149,7 @@ END%%

 %%ANKI
 Basic
-What is the `END` pattern?
+How is the `END` pattern interpreted?
 Back: Code associated with it executes after all input has been read.
 Reference: Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
 <!--ID: 1706823790239-->
@ -188,6 +188,49 @@ Reference: Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 202
 <!--ID: 1706824091128-->
 END%%

+`awk` is said to be a "line-oriented" language. Every rule's action must begin on the same line as the pattern.
+
+%%ANKI
+Basic
+When can a rule's pattern and action exist on different lines?
+Back: Only when using backslash continuation.
+Reference: Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
+<!--ID: 1706883732944-->
+END%%
+
+## Variables
+
+Variables are defined like `var=val`. They can be specified in two different places:
+
+1. Via the `-v` command line flag. Using this allows accessing the variable value from within a `BEGIN` rule.
+2. In the file list. Using this allows accessing the variable value in all subsequent file processing.
+
+%%ANKI
+Basic
+Where in an `awk` invocation can variables be assigned?
+Back: As a `-v` argument or in the file list.
+Reference: Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
+<!--ID: 1706885111450-->
+END%%
+
+%%ANKI
+Basic
+The `-v` flag was introduced to accommodate what functionality?
+Back: Accessing variables from a `BEGIN` rule.
+Reference: Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
+<!--ID: 1706885111454-->
+END%%
+
+%%ANKI
+Basic
+Describe what the following command does in in a single sentence:
+```bash
+$ awk 'program' pass=1 data pass=2 data
+```
+Back: Evaluates `'program'` against the `data` file twice with a different value of `pass` on each run.
+Reference: Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
+<!--ID: 1706885111457-->
+END%%
 ## References

 * Robbins, Arnold D. “GAWK: Effective AWK Programming,” October 2023. [https://www.gnu.org/software/gawk/manual/gawk.pdf](https://www.gnu.org/software/gawk/manual/gawk.pdf)
--- a/notes/journal/2024-02-02.md
+++ b/notes/journal/2024-02-02.md
@ -0,0 +1,14 @@
+---
+title: "2024-02-02"
+---
+
+- [x] Anki Flashcards
+- [x] KoL
+- [x] Sheet Music (10 min.)
+- [x] OGS (1 Life & Death Problem)
+- [x] Korean (Read 1 Story)
+- [ ] Interview Prep (1 Practice Problem)
+- [ ] Log Work Hours (Max 3 hours)
+
+* Read 효자 호랑이 (The Filial Tiger).
+* Read through [Project #1 - Buffer Pool](https://15445.courses.cs.cmu.edu/fall2022/project1/) in anticipation of my call with Kevin later.