From 25ef5d5a5fed1e2f95e57115dfdbc8ba67cfc93f Mon Sep 17 00:00:00 2001
From: Clumsy-Coder <19594044+Clumsy-Coder@users.noreply.github.com>
Date: Thu, 11 Aug 2022 20:37:54 -0600
Subject: [PATCH 1/2] feat(shell): run shell command conditionally

  ## what
  - add feature to run shell command (optionally)

  ## how
  - the shell directive will check if the 'if' property is available.
    If it is, it will run the command in 'if' property.
    If the command results in a return 0 code or 'true', then the
    'command' property will run.
    If the condition to run the command is a non 0 code or 'false',
      the shell command won't run
  - dotbot config example:
    ```yaml
    - shell:
        - command: echo "this is running on a MacOS"
          if: uname -s | grep -i "Darwin"
    ```
  - dotbot config example: skipping command if false
    ```yaml
    - shell:
        - command: echo "This command should be skipped"
          if: false
    ```

  ## why
  - can run the shell command conditionally
  - can use multiple dotbot configs to run different OS
    - Ex: incorporating it in https://github.com/ecarlson94/dotbot-template

  ## where
  - file changed in `./dotbot/plugins/shell.py`

  ## usage
  Create dotbot config
    ```yaml
    - shell:
        - command: echo "this is running on a MacOS"
          if: uname -s | grep -i "Darwin"
    ```

    ```yaml
    - shell:
        - command: echo "This command should be skipped"
          if: false
    ```
---
 dotbot/plugins/shell.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/dotbot/plugins/shell.py b/dotbot/plugins/shell.py
index bbdcb6d..ee12719 100644
--- a/dotbot/plugins/shell.py
+++ b/dotbot/plugins/shell.py
@@ -36,6 +36,30 @@ class Shell(dotbot.Plugin):
                 stdout = item.get("stdout", stdout)
                 stderr = item.get("stderr", stderr)
                 quiet = item.get("quiet", quiet)
+
+                # run shell command if the 'if' key is present
+                # Ex:
+                # - shell:
+                #     - command: echo "This computer is a Mac"
+                #       if: uname -s | grep -i "Darwin"
+                #
+                # Ex: skipping shell command
+                # - shell:
+                #     - command: echo "skip this shell command"
+                #       if: false
+                if "if" in item:
+                    run_if_result = dotbot.util.shell_command(
+                        str(item["if"]),        # this to make sure python doesn't run it. Had a odd behaviour with having the value 'false'. Check Pull Request #321
+                        cwd=self._context.base_directory(),
+                        enable_stdin=False,
+                        enable_stdout=False,
+                        enable_stderr=stderr,
+                    )
+
+                    # if the condition to run the command is false,
+                    # skip running the command
+                    if run_if_result != 0:
+                        continue
             elif isinstance(item, list):
                 cmd = item[0]
                 msg = item[1] if len(item) > 1 else None

From 974156ccdecee05eb9544b0b21cc0351428ddd43 Mon Sep 17 00:00:00 2001
From: Clumsy-Coder <19594044+Clumsy-Coder@users.noreply.github.com>
Date: Thu, 11 Aug 2022 21:12:47 -0600
Subject: [PATCH 2/2] docs(readme): add docs for using shell conditionally

  ## what
  - add documentation on using shell command conditionally

  ## how

  ## why

  ## where

  ## usage
---
 README.md | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/README.md b/README.md
index 9cdea47..a32aaf7 100644
--- a/README.md
+++ b/README.md
@@ -332,6 +332,7 @@ fine-grained control.
 | `stdin` | Allow a command to read from standard input (default: false) |
 | `stdout` | Show a command's output from stdout (default: false) |
 | `stderr` | Show a command's error output from stderr (default: false) |
+| `if` | Run command if a condition is true (default: true) (optional) |
 
 Note that `quiet` controls whether the command (a string) is printed in log
 output, it does not control whether the output from running the command is
@@ -356,6 +357,19 @@ printed (that is controlled by `stdout` / `stderr`). When a command's `stdin` /
     stderr: true
 ```
 
+##### Running shell command conditionally
+
+```yaml
+- shell:
+    - command: apt update && apt upgrade -y
+      if: lsb_release -i | grep -io 'debian'
+      description: Update APT package repository
+
+    - command: dnf update -y
+      if: lsb_release -i | grep -io 'fedora'
+      description: Update DNF package repository
+```
+
 ### Clean
 
 Clean commands specify directories that should be checked for dead symbolic