Created install.func - script function explanations (markdown)

install.func-‐-script-function-explanations.md

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+# Debian/Ubuntu Container Setup Script Function Explanations
+
+## 1. `color()`
+**Purpose**: Sets up various color and formatting variables for terminal output.
+
+### Details:
+- Defines colors like yellow (`YW`), green (`GN`), and red (`RD`) using ANSI escape codes for text formatting.
+- Also defines icons for different types of output, such as checkmarks (`CM`), error crosses (`CROSS`), and network-related icons (`NETWORK`, `GATEWAY`).
+
+### Example:
+```bash
+color
+echo -e "${GN}Success${CL}"   # Output: Green colored "Success"
+echo -e "${NETWORK}Network${CL}"  # Network icon followed by text "Network"
+```
+
+---
+
+## 2. `verb_ip6()`
+**Purpose**: Enables or disables IPv6 based on the `DISABLEIPV6` variable and sets the verbose mode.
+
+### Details:
+- Disables IPv6 by adding a line to `/etc/sysctl.conf` if `DISABLEIPV6` is set to `yes`.
+- Optionally suppresses output based on the `VERBOSE` variable.
+
+### Example:
+```bash
+DISABLEIPV6="yes"
+verb_ip6  # Disables IPv6 if the variable is set
+```
+
+---
+
+## 3. `catch_errors()`
+**Purpose**: Sets up error handling for the script.
+
+### Details:
+- Configures the script to exit immediately on errors using `set -Eeuo pipefail`.
+- Defines a trap that calls `error_handler()` when an error occurs.
+
+### Example:
+```bash
+catch_errors
+ls non_existent_file  # This will trigger the error handler
+```
+
+---
+
+## 4. `error_handler()`
+**Purpose**: Handles errors that occur during script execution.
+
+### Details:
+- Stops the spinner if it's running.
+- Prints the error message with details like the exit code, line number, and the command that failed.
+
+### Example:
+```bash
+error_handler 42 "ls non_existent_file"
+# Output: [ERROR] in line 42: exit code 2: while executing command "ls non_existent_file"
+```
+
+---
+
+## 5. `spinner()`
+**Purpose**: Displays a rotating spinner animation.
+
+### Details:
+- Uses a set of frames to create a spinning effect in the terminal.
+
+### Example:
+```bash
+spinner  # Starts the spinner animation
+```
+
+---
+
+## 6. `msg_info()`, `msg_ok()`, `msg_error()`
+**Purpose**: Displays messages with different statuses.
+
+### Details:
+- `msg_info()`: Displays an informational message with a spinner animation.
+- `msg_ok()`: Displays a success message and stops the spinner.
+- `msg_error()`: Displays an error message and stops the spinner.
+
+### Example:
+```bash
+msg_info "This is an informational message"
+msg_ok "Success!"
+msg_error "An error occurred"
+```
+
+---
+
+## 7. `setting_up_container()`
+**Purpose**: Sets up the container OS, configures locale, timezone, and network.
+
+### Details:
+- Modifies `/etc/locale.gen` to enable the correct locale.
+- Configures timezone and network, retrying network configuration if necessary.
+
+### Example:
+```bash
+setting_up_container  # Configures OS, locale, timezone, and network
+```
+
+---
+
+## 8. `network_check()`
+**Purpose**: Verifies internet connectivity via IPv4 and IPv6.
+
+### Details:
+- Checks IPv4 connectivity to Google, Cloudflare, and Quad9 DNS servers.
+- Checks IPv6 connectivity and performs DNS lookup for `github.com`.
+
+### Example:
+```bash
+network_check  # Verifies internet connectivity
+```
+
+---
+
+## 9. `update_os()`
+**Purpose**: Updates the container's OS using `apt-get update` and `apt-get dist-upgrade`.
+
+### Details:
+- If `CACHER` is enabled, it configures a proxy for package fetching.
+- Runs system update and upgrades all installed packages.
+
+### Example:
+```bash
+update_os  # Updates the container's OS
+```
+
+---
+
+## 10. `motd_ssh()`
+**Purpose**: Modifies the message of the day (MOTD) and SSH settings.
+
+### Details:
+- Sets terminal to 256-color mode and updates `/etc/motd` with system information.
+- Configures SSH settings to allow root login if enabled.
+
+### Example:
+```bash
+motd_ssh  # Modifies MOTD and SSH settings
+```
+
+---
+
+## 11. `customize()`
+**Purpose**: Customizes the container by enabling auto-login and setting up SSH keys.
+
+### Details:
+- If no password is provided, it enables auto-login for the root user.
+- Optionally configures SSH by adding the provided public key to the root user.
+
+### Example:
+```bash
+customize  # Customizes the container with auto-login and SSH key setup
+```
+