feat: Add 'command_exists' precondition type

Cargo.lock

@@ -275,6 +275,16 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
 
+[[package]]
+name = "errno"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "534c5cf6194dfab3db3242765c03bbe257cf92f22b38f6bc0c58d59108a820ba"
+dependencies = [
+ "libc",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "filedescriptor"
 version = "0.8.2"
@@ -308,6 +318,15 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
+[[package]]
+name = "home"
+version = "0.5.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3d1354bf6b7235cb4a0576c2619fd4ed18183f689b12b006a0ee7329eeff9a5"
+dependencies = [
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "iana-time-zone"
 version = "0.1.60"
@@ -411,6 +430,12 @@ version = "0.2.155"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "97b3888a4aecf77e811145cadf6eef5901f4782c53886191b2f693f24761847c"
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78b3ae25bc7c8c38cec158d1f2757ee79e9b3740fbc7ccf0e59e4b08d793fa89"
+
 [[package]]
 name = "lock_api"
 version = "0.4.12"
@@ -648,6 +673,19 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "rustix"
+version = "0.38.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70dc5ec042f7a43c4a73241207cecc9873a06d45debb38b329f8541d85c2730f"
+dependencies = [
+ "bitflags 2.5.0",
+ "errno",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.17"
@@ -933,6 +971,7 @@ dependencies = [
  "tempdir",
  "toml",
  "tui-term",
+ "which",
 ]
 
 [[package]]
@@ -1079,6 +1118,18 @@ version = "0.2.92"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af190c94f2773fdb3729c55b007a722abb5384da03bc0986df4c289bf5567e96"
 
+[[package]]
+name = "which"
+version = "6.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d9c5ed668ee1f17edb3b627225343d210006a90bb1e3745ce1f30b1fb115075"
+dependencies = [
+ "either",
+ "home",
+ "rustix",
+ "winsafe",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.9"
@@ -1267,6 +1318,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "winsafe"
+version = "0.0.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d135d17ab770252ad95e9a872d365cf3090e3be864a34ab46f48555993efc904"
+
 [[package]]
 name = "zerocopy"
 version = "0.7.34"

Cargo.toml

@@ -16,6 +16,7 @@ include_dir = "0.7.4"
 tempdir = "0.3.7"
 serde = { version = "1.0.205", features = ["derive"] }
 toml = "0.8.19"
+which = "6.0.2"
 
 [[bin]]
 name = "linutil"

src/tabs.rs

@@ -50,6 +50,9 @@ impl Entry {
                                     == *matches
                             })
                         }
+                        SystemDataType::CommandExists => values
+                            .iter()
+                            .all(|command| which::which(command).is_ok() == *matches),
                     }
                 },
             )
@@ -72,6 +75,8 @@ enum SystemDataType {
     Environment(String),
     #[serde(rename = "file")]
     File(PathBuf),
+    #[serde(rename = "command_exists")]
+    CommandExists,
 }
 
 #[derive(Hash, Eq, PartialEq)]