From 06834eea8b7ae7b98c81342becbe56717351ab57 Mon Sep 17 00:00:00 2001
From: Christian Meusel <christian.meusel@posteo.de>
Date: Tue, 30 Sep 2025 22:50:12 +0200
Subject: [PATCH 1/2] Derive Debug for Cli

Because it should.
---
 src/main.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 11c6499..b4a20a7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -12,7 +12,7 @@ use gpio_utils::config::{self, GpioConfig};
 use gpio_utils::options::*;
 use std::process;
 
-#[derive(Parser)]
+#[derive(Debug, Parser)]
 #[command(
     name = "GPIO Utils",
     version,
@@ -26,7 +26,7 @@ struct Cli {
     command: Commands,
 }
 
-#[derive(Subcommand)]
+#[derive(Debug, Subcommand)]
 enum Commands {
     /// Read the value of a GPIO Input
     Read {

From 1b1df13ec17b63697e70911b5bb3bdcb082d9e6c Mon Sep 17 00:00:00 2001
From: Christian Meusel <christian.meusel@posteo.de>
Date: Tue, 30 Sep 2025 22:53:21 +0200
Subject: [PATCH 2/2] Allow specifying two common options via env

Configuration files an symlink root are used in many subcommands and are
expected to be fixed for a certain environment. Allow to conveniently pass them
via environment variables.

The symlink root has a somewhat special role as it might as well be specified
via configuration files and we can't have a default value from the CLI in this
case.
---
 Cargo.toml  |  2 +-
 src/main.rs | 15 +++++++++------
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index b20a1f7..9cb80a4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,7 +17,7 @@ Rust applications or any other applications.
 """
 
 [dependencies]
-clap = { version = "4.5.48", features = ["derive"] }
+clap = { version = "4.5.48", features = ["derive", "env"] }
 sysfs_gpio = "0.6.2"
 toml = { version = "<=0.9.6", default-features = false, features = ["parse", "serde"] }
 glob = "0.3.3"
diff --git a/src/main.rs b/src/main.rs
index b4a20a7..14dce07 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -12,6 +12,9 @@ use gpio_utils::config::{self, GpioConfig};
 use gpio_utils::options::*;
 use std::process;
 
+pub const CONFIG_ENV_VAR: &str = "GPIO_UTILS_CONFIG";
+pub const SYMLINK_ROOT_ENV_VAR: &str = "GPIO_UTILS_SYMLINK_ROOT";
+
 #[derive(Debug, Parser)]
 #[command(
     name = "GPIO Utils",
@@ -19,8 +22,8 @@ use std::process;
     about = "Read, Write, and Configure GPIOs"
 )]
 struct Cli {
-    /// additional configuration to use
-    #[arg(short, long = "config", value_name = "FILE")]
+    /// additional configuration to use (separator ':')
+    #[arg(short, long = "config", value_name = "FILE", num_args = 0.., env = CONFIG_ENV_VAR, value_delimiter = ':')]
     configs: Vec<String>,
     #[command(subcommand)]
     command: Commands,
@@ -56,13 +59,13 @@ enum Commands {
         /// The pin name (or number)
         pin: String,
         /// root directory for export symlinks
-        #[arg(short = 'r', long)]
+        #[arg(short = 'r', long, env = SYMLINK_ROOT_ENV_VAR)]
         symlink_root: Option<String>,
     },
     /// Export all configured GPIOs
     ExportAll {
         /// Export all configured GPIOs
-        #[arg(short = 'r', long)]
+        #[arg(short = 'r', long, env = SYMLINK_ROOT_ENV_VAR)]
         symlink_root: Option<String>,
     },
     /// Export all configured GPIOs
@@ -70,13 +73,13 @@ enum Commands {
         /// The pin name (or number)
         pin: String,
         /// root directory for export symlinks
-        #[arg(short = 'r', long)]
+        #[arg(short = 'r', long, env = SYMLINK_ROOT_ENV_VAR)]
         symlink_root: Option<String>,
     },
     /// Unexport all configured, exported GPIOs
     UnexportAll {
         /// root directory for export symlinks
-        #[arg(short = 'r', long)]
+        #[arg(short = 'r', long, env = SYMLINK_ROOT_ENV_VAR)]
         symlink_root: Option<String>,
     },
     /// Output status of a GPIO or all GPIOs if no pin is specified