dd: Error message of invalid args is matched with GNU

src/uu/dd/src/dd.rs

@@ -146,7 +146,7 @@ impl Input<File> {
                 }
 
                 opts.open(fname)
-                    .map_err_context(|| "failed to open input file".to_string())?
+                    .map_err_context(|| format!("failed to open {}", fname.quote()))?
             };
 
             // The --skip and --iseek flags are additive. On a file, they seek.

src/uu/dd/src/parseargs.rs

@@ -35,6 +35,7 @@ pub enum ParseError {
     IbsOutOfRange,
     ObsOutOfRange,
     CbsOutOfRange,
+    InvalidNumber(String),
 }
 
 impl ParseError {
@@ -56,6 +57,7 @@ impl ParseError {
             Self::IbsOutOfRange => Self::IbsOutOfRange,
             Self::ObsOutOfRange => Self::ObsOutOfRange,
             Self::CbsOutOfRange => Self::CbsOutOfRange,
+            Self::InvalidNumber(_) => Self::InvalidNumber(s),
         }
     }
 }
@@ -79,7 +81,12 @@ impl std::fmt::Display for ParseError {
                 write!(f, "Only one ov conv=excl or conv=nocreat may be specified")
             }
             Self::FlagNoMatch(arg) => {
-                write!(f, "Unrecognized iflag=FLAG or oflag=FLAG -> {}", arg)
+                // Additional message about 'dd --help' is displayed only in this situation.
+                write!(
+                    f,
+                    "invalid input flag: ‘{}’\nTry 'dd --help' for more information.",
+                    arg
+                )
             }
             Self::ConvFlagNoMatch(arg) => {
                 write!(f, "Unrecognized conv=CONV -> {}", arg)
@@ -115,6 +122,9 @@ impl std::fmt::Display for ParseError {
             Self::Unimplemented(arg) => {
                 write!(f, "feature not implemented on this system -> {}", arg)
             }
+            Self::InvalidNumber(arg) => {
+                write!(f, "invalid number: ‘{}’", arg)
+            }
         }
     }
 }
@@ -389,7 +399,7 @@ fn parse_bytes_no_x(s: &str) -> Result<u64, ParseError> {
         (None, None, None) => match uucore::parse_size::parse_size(s) {
             Ok(n) => (n, 1),
             Err(ParseSizeError::InvalidSuffix(s)) | Err(ParseSizeError::ParseFailure(s)) => {
-                return Err(ParseError::MultiplierStringParseFailure(s))
+                return Err(ParseError::InvalidNumber(s))
             }
             Err(ParseSizeError::SizeTooBig(s)) => {
                 return Err(ParseError::MultiplierStringOverflow(s))

tests/by-util/test_dd.rs

@@ -1187,3 +1187,62 @@ fn test_final_stats_si_iec() {
     let s = result.stderr_str();
     assert!(s.starts_with("2+0 records in\n2+0 records out\n1024 bytes (1 KB, 1024 B) copied,"));
 }
+
+#[test]
+fn test_invalid_number_arg_gnu_compatibility() {
+    let commands = vec!["bs", "cbs", "count", "ibs", "obs", "seek", "skip"];
+
+    for command in commands {
+        new_ucmd!()
+            .args(&[format!("{}=", command)])
+            .fails()
+            .stderr_is("dd: invalid number: ‘’");
+
+        new_ucmd!()
+            .args(&[format!("{}=29d", command)])
+            .fails()
+            .stderr_is("dd: invalid number: ‘29d’");
+    }
+}
+
+#[test]
+fn test_invalid_flag_arg_gnu_compatibility() {
+    let commands = vec!["iflag", "oflag"];
+
+    for command in commands {
+        new_ucmd!()
+            .args(&[format!("{}=", command)])
+            .fails()
+            .stderr_is("dd: invalid input flag: ‘’\nTry 'dd --help' for more information.");
+
+        new_ucmd!()
+            .args(&[format!("{}=29d", command)])
+            .fails()
+            .stderr_is("dd: invalid input flag: ‘29d’\nTry 'dd --help' for more information.");
+    }
+}
+
+#[test]
+fn test_invalid_file_arg_gnu_compatibility() {
+    new_ucmd!()
+        .args(&["if="])
+        .fails()
+        .stderr_is("dd: failed to open '': No such file or directory");
+
+    new_ucmd!()
+        .args(&["if=81as9bn8as9g302az8ns9.pdf.zip.pl.com"])
+        .fails()
+        .stderr_is(
+            "dd: failed to open '81as9bn8as9g302az8ns9.pdf.zip.pl.com': No such file or directory",
+        );
+
+    new_ucmd!()
+        .args(&["of="])
+        .fails()
+        .stderr_is("dd: failed to open '': No such file or directory");
+
+    new_ucmd!()
+        .args(&["of=81as9bn8as9g302az8ns9.pdf.zip.pl.com"])
+        .pipe_in("")
+        .succeeds();
+}