fix: allow hyphen values to -r/--line-range

via #2944

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ## Bugfixes
 
+- Fix negative values of N not being parsed in <N:M> line ranges without `=` flag value separator, see #3442 (@lmmx)
+
 ## Other
 
 ## Syntaxes

doc/long-help.txt

@@ -194,6 +194,7 @@ Options:
             '--line-range :40' prints lines 1 to 40
             '--line-range 40:' prints lines 40 to the end of the file
             '--line-range 40' only prints line 40
+            '--line-range -10:' prints the last 10 lines
             '--line-range 30:+10' prints lines 30 to 40
             '--line-range 35::5' prints lines 30 to 40 (line 35 with 5 lines of context)
             '--line-range 30:40:2' prints lines 28 to 42 (range 30-40 with 2 lines of context)

src/bin/bat/clap_app.rs

@@ -519,6 +519,7 @@ pub fn build_app(interactive_output: bool) -> Command {
                 .short('r')
                 .action(ArgAction::Append)
                 .value_name("N:M")
+                .allow_hyphen_values(true)
                 .help("Only print the lines from N to M.")
                 .long_help(
                     "Only print the specified range of lines for each file. \
@@ -527,6 +528,7 @@ pub fn build_app(interactive_output: bool) -> Command {
                      '--line-range :40' prints lines 1 to 40\n  \
                      '--line-range 40:' prints lines 40 to the end of the file\n  \
                      '--line-range 40' only prints line 40\n  \
+                     '--line-range -10:' prints the last 10 lines\n  \
                      '--line-range 30:+10' prints lines 30 to 40\n  \
                      '--line-range 35::5' prints lines 30 to 40 (line 35 with 5 lines of context)\n  \
                      '--line-range 30:40:2' prints lines 28 to 42 (range 30-40 with 2 lines of context)",

tests/integration_tests.rs

@@ -207,7 +207,7 @@ fn line_range_from_back_last_two() {
 }
 
 #[test]
-fn line_range_from_back_last_two_single_line() {
+fn line_range_from_back_last_two_single_line_eq_sep() {
     bat()
         .arg("single-line.txt")
         .arg("--line-range=-2:")
@@ -216,6 +216,17 @@ fn line_range_from_back_last_two_single_line() {
         .stdout("Single Line");
 }
 
+#[test]
+fn line_range_from_back_last_two_single_line_no_sep() {
+    bat()
+        .arg("single-line.txt")
+        .arg("--line-range")
+        .arg("-2:")
+        .assert()
+        .success()
+        .stdout("Single Line");
+}
+
 #[test]
 fn line_range_first_two() {
     bat()