cut: improve some error messages

src/uu/cut/locales/en-US.ftl

@@ -109,6 +109,6 @@ cut-error-delimiter-and-whitespace-conflict = invalid input: Only one of --delim
 cut-error-delimiter-must-be-single-character = the delimiter must be a single character
 cut-error-multiple-mode-args = invalid usage: expects no more than one of --fields (-f), --chars (-c) or --bytes (-b)
 cut-error-missing-mode-arg = invalid usage: expects one of --fields (-f), --chars (-c) or --bytes (-b)
-cut-error-delimiter-only-with-fields = invalid input: The '--delimiter' ('-d') option only usable if printing a sequence of fields
-cut-error-whitespace-only-with-fields = invalid input: The '-w' option only usable if printing a sequence of fields
-cut-error-only-delimited-only-with-fields = invalid input: The '--only-delimited' ('-s') option only usable if printing a sequence of fields
+cut-error-delimiter-only-with-fields = invalid input: The '--delimiter' ('-d') option can only be used when printing a sequence of fields
+cut-error-whitespace-only-with-fields = invalid input: The '-w' option can only be used when printing a sequence of fields
+cut-error-only-delimited-only-with-fields = invalid input: The '--only-delimited' ('-s') option can only be used when printing a sequence of fields

tests/by-util/test_cut.rs

@@ -131,7 +131,7 @@ fn test_delimiter_with_byte_and_char() {
         new_ucmd!()
             .args(&[conflicting_arg, COMPLEX_SEQUENCE.sequence, "-d="])
             .fails_with_code(1)
-            .stderr_is("cut: invalid input: The '--delimiter' ('-d') option only usable if printing a sequence of fields\n")
+            .stderr_is("cut: invalid input: The '--delimiter' ('-d') option can only be used when printing a sequence of fields\n")
 ;
     }
 }

util/gnu-patches/tests_cut_error_msg.patch

@@ -21,7 +21,7 @@ Index: gnu/tests/cut/cut.pl
 +my $inval_fld = "$prog: range '--' was invalid: failed to parse range\n";
 +my $inval_pos = "$prog: range '--' was invalid: failed to parse range\n";
 +my $no_endpoint = "$prog: range '-' was invalid: invalid range with no endpoint\n";
-+my $nofield = "$prog: invalid input: The '--delimiter' ('-d') option only usable if printing a sequence of fields\n";
++my $nofield = "$prog: invalid input: The '--delimiter' ('-d') option can only be used when printing a sequence of fields\n";
 
  my @Tests =
   (
@@ -53,7 +53,7 @@ Index: gnu/tests/cut/cut.pl
    ['y', qw(-s -b4), {IN=>":\n"}, {OUT=>""}, {EXIT=>1},
 -   {ERR=>"$prog: suppressing non-delimited lines makes sense\n"
 -    . "\tonly when operating on fields\n$try"}],
-+   {ERR=>"$prog: invalid input: The '--only-delimited' ('-s') option only usable if printing a sequence of fields\n"}],
++   {ERR=>"$prog: invalid input: The '--only-delimited' ('-s') option can only be used when printing a sequence of fields\n"}],
    # You must specify bytes or fields (or chars)
    ['z', '', {IN=>":\n"}, {OUT=>""}, {EXIT=>1},
 -   {ERR=>"$prog: you must specify a list of bytes, characters, or fields\n$try"}