feat: support DOTM_DIR env var for dotfiles directory

Cargo.toml

@@ -20,7 +20,7 @@ path = "src/main.rs"
 
 [dependencies]
 anyhow = "1"
-clap = { version = "4", features = ["derive"] }
+clap = { version = "4", features = ["derive", "env"] }
 clap_complete = "4"
 dirs = "6"
 fs2 = "0.4"
@@ -29,7 +29,10 @@ serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 tera = "1"
 crossterm = "0.29"
-gix = { version = "0.84", default-features = false, features = ["revision", "sha1"] }
+gix = { version = "0.84", default-features = false, features = [
+  "revision",
+  "sha1",
+] }
 nix = { version = "0.31", features = ["user", "fs"] }
 sha2 = "0.11"
 shellexpand = "3"

README.md

@@ -152,7 +152,7 @@ Variable precedence: **host vars > role vars** (last role listed wins among role
 Override files sit next to the base file with a `##` suffix:
 
 | Pattern | Priority | Description |
-|---------|----------|-------------|
+| --------- | ---------- | ------------- |
 | `file##host.<hostname>` | 1 (highest) | Used only on the named host |
 | `file##role.<rolename>` | 2 | Used when the role is active |
 | `file.tera` | 3 | Tera template, rendered with vars |
@@ -329,7 +329,7 @@ dotm adopt             # interactively adopt external changes back into source
 Status markers:
 
 | Marker | Meaning |
-|--------|---------|
+| -------- | --------- |
 | `~` | File is OK (verbose mode only) |
 | `M` | Content has been modified since last deploy |
 | `!` | File is missing |
@@ -343,7 +343,7 @@ If a file was modified externally, re-deploying will skip it with a warning. Use
 dotm [OPTIONS] <COMMAND>
 
 Options:
-  -d, --dir <DIR>   Path to dotfiles directory [default: .]
+  -d, --dir <DIR>   Path to dotfiles directory (env: DOTM_DIR) [default: .]
   -V, --version     Print version
 
 Commands:
@@ -490,7 +490,7 @@ dotm sync --system             # sync system packages
 ## Comparison
 
 | Feature | dotm | GNU stow | yadm | dotter |
-|---------|------|----------|------|--------|
+| --------- | ------ | ---------- | ------ | -------- |
 | Symlink-based | Yes | Yes | Yes | Yes |
 | Role/profile system | Yes | No | No | Yes |
 | Host-specific overrides | Yes | No | Alt files | Yes |

src/main.rs

@@ -10,7 +10,7 @@ use std::path::PathBuf;
 )]
 struct Cli {
     /// Path to the dotfiles directory (default: current directory)
-    #[arg(short, long, default_value = ".")]
+    #[arg(short, long, env = "DOTM_DIR", default_value = ".")]
     dir: PathBuf,
 
     #[command(subcommand)]

tests/cli.rs

@@ -179,6 +179,37 @@ fn cli_list_hosts() {
         .stdout(predicate::str::contains("testhost"));
 }
 
+#[test]
+fn cli_dotm_dir_env_var() {
+    let dotfiles = TempDir::new().unwrap();
+    copy_dir_recursive(Path::new("tests/fixtures/basic"), dotfiles.path());
+
+    // Without --dir, DOTM_DIR env var should be used
+    Command::cargo_bin("dotm")
+        .unwrap()
+        .env("DOTM_DIR", dotfiles.path().to_str().unwrap())
+        .args(["list", "packages"])
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("shell"));
+}
+
+#[test]
+fn cli_dir_flag_overrides_dotm_dir_env() {
+    let dotfiles = TempDir::new().unwrap();
+    let empty = TempDir::new().unwrap();
+    copy_dir_recursive(Path::new("tests/fixtures/basic"), dotfiles.path());
+
+    // --dir flag should take precedence over DOTM_DIR
+    Command::cargo_bin("dotm")
+        .unwrap()
+        .env("DOTM_DIR", empty.path().to_str().unwrap())
+        .args(["-d", dotfiles.path().to_str().unwrap(), "list", "packages"])
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("shell"));
+}
+
 #[test]
 fn cli_list_hosts_tree() {
     let dotfiles = TempDir::new().unwrap();