test code with bash

posts/test.md

@@ -57,18 +57,93 @@ draft: true
 
 ## 4. Code Blocks with Syntax Highlighting
 
-```nix
-{ config, pkgs, ... }:
+```bash
+#!/usr/bin/env bash
+set -euo pipefail
 
-{
-  environment.systemPackages = with pkgs; [
-    git
-    neovim
-    tmux
-  ];
+# Variables & string manipulation
+NAME="world"
+GREETING="Hello, ${NAME}!"
+UPPER=${GREETING^^}
+SLICE=${GREETING:0:5}
+echo "$UPPER | $SLICE"
 
-  nix.settings.experimental-features = [ "nix-command" "flakes" ];
+# Arrays
+FRUITS=(apple banana cherry)
+FRUITS+=(mango)
+echo "${FRUITS[@]}"          # all elements
+echo "${#FRUITS[@]}"         # length
+echo "${FRUITS[@]:1:2}"      # slice
+
+# Associative array
+declare -A CONFIG=([host]="localhost" [port]="8080")
+echo "${CONFIG[host]}:${CONFIG[port]}"
+
+# Arithmetic
+COUNT=0
+(( COUNT += 5 ))
+RESULT=$(( COUNT ** 2 ))
+echo "$RESULT"
+
+# Conditionals & test operators
+FILE="/etc/hosts"
+if [[ -f "$FILE" && -r "$FILE" ]]; then
+  echo "readable"
+elif [[ -e "$FILE" ]]; then
+  echo "exists but not readable"
+else
+  echo "not found"
+fi
+
+# Case
+case "$NAME" in
+  world|earth) echo "planet" ;;
+  *) echo "unknown" ;;
+esac
+
+# Loops
+for fruit in "${FRUITS[@]}"; do
+  echo "fruit: $fruit"
+done
+
+for (( i=0; i<3; i++ )); do
+  echo "i=$i"
+done
+
+WHILE=3
+while (( WHILE-- > 0 )); do
+  echo "while: $WHILE"
+done
+
+# Functions with local vars & return codes
+greet() {
+  local name=${1:-"stranger"}
+  local -r greeting="Hi, $name!"
+  echo "$greeting"
+  return 0
 }
+greet "$NAME"
+
+# Command substitution & process substitution
+DATE=$(date +%Y-%m-%d)
+DIFF=<(echo "foo") 
+echo "Today: $DATE"
+
+# Here-doc
+cat <<EOF
+Multiline
+  text block
+EOF
+
+# Pipelines, redirection & traps
+trap 'echo "exiting"; exit 1' ERR
+echo "hello" | tr '[:lower:]' '[:upper:]' > /dev/null 2>&1
+
+# Parameter expansion: default, error, replace
+echo "${UNSET:-default}"
+echo "${GREETING/Hello/Hey}"
+echo "${FILE##*/}"   # basename
+echo "${FILE%/*}"    # dirname
 ```
 
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