refactor(cli): change the way in which the output path is passed to the compile command

The output path was passed as the last positional argument for the command, but this have an inconvenience. If the user pass multiple input files and forgets to specify an output path, the last input path is used as output and the input file is overwritten.

In order to prevent this, the output path is now passed with the `--output` option. If the option is missing, the default path `output.yarc` is used.

Closes #126.

Author: plusvic

cli/src/commands/compile.rs

@@ -17,17 +17,10 @@ pub fn compile() -> Command {
                 .action(ArgAction::Append),
         )
         .arg(
-            arg!(<OUTPUT_PATH>)
-                .help("Path to file with compiled results")
-                .value_parser(value_parser!(PathBuf)),
-        )
-        .arg(
-            arg!(--"path-as-namespace")
-                .help("Use file path as rule namespace"),
-        )
-        .arg(
-            arg!(--"relaxed-re-syntax")
-                .help("Use a more relaxed syntax check while parsing regular expressions"),
+            arg!(-o --"output" <OUTPUT_PATH>)
+                .help("Output file with compiled results")
+                .default_value("output.yarc")
+                .value_parser(value_parser!(PathBuf))
         )
         .arg(
             Arg::new("define")
@@ -40,12 +33,20 @@ pub fn compile() -> Command {
                 .value_parser(external_var_parser)
                 .action(ArgAction::Append),
         )
+        .arg(
+            arg!(--"path-as-namespace")
+                .help("Use file path as rule namespace"),
+        )
+        .arg(
+            arg!(--"relaxed-re-syntax")
+                .help("Use a more relaxed syntax check while parsing regular expressions"),
+        )
 }
 
 pub fn exec_compile(args: &ArgMatches) -> anyhow::Result<()> {
     let rules_path = args.get_many::<PathBuf>("RULES_PATH").unwrap();
-    let output_path = args.get_one::<PathBuf>("OUTPUT_PATH").unwrap();
     let path_as_namespace = args.get_flag("path-as-namespace");
+    let output_path = args.get_one::<PathBuf>("output").unwrap();
 
     let external_vars: Option<Vec<(String, serde_json::Value)>> = args
         .get_many::<(String, serde_json::Value)>("define")

site/content/docs/intro/cli.md

@@ -160,15 +160,17 @@ re-used for multiple scan operations.
 The syntax for this command is:
 
 ```
-yr compile [OPTIONS] <RULES_PATH>... <OUTPUT_PATH>
+yr compile [OPTIONS] <RULES_PATH>...
 ```
 
 Each `<RULES_PATH>` is the path of YARA source file or a directory containing
 source files. When`<RULES_PATH>` is a directory YARA-X iterates the directory
 recursively looking for any `*.yar` or `*.yara` files.
 
-The `<OUTPUT_PATH>` is the path of the output binary file. The supported
-options are:
+### --output, -o <OUTPUT_PATH>
+
+Specify the path for the output binary file containing the compiled rules. By
+default, is `output.yarc`.
 
 ### --relaxed-re-syntax