diff options
| -rw-r--r-- | findutils/grep.c | 10 | ||||
| -rwxr-xr-x | testsuite/grep.tests | 4 |
2 files changed, 11 insertions, 3 deletions
diff --git a/findutils/grep.c b/findutils/grep.c index 688ea6ab2..024f27609 100644 --- a/findutils/grep.c +++ b/findutils/grep.c @@ -461,15 +461,19 @@ static int grep_file(FILE *file) if (found) print_line(gl->pattern, strlen(gl->pattern), linenum, ':'); } else while (1) { + unsigned start = gl->matched_range.rm_so; unsigned end = gl->matched_range.rm_eo; + unsigned len = end - start; char old = line[end]; line[end] = '\0'; - print_line(line + gl->matched_range.rm_so, - end - gl->matched_range.rm_so, - linenum, ':'); + /* Empty match is not printed: try "echo test | grep -o ''" */ + if (len != 0) + print_line(line + start, len, linenum, ':'); if (old == '\0') break; line[end] = old; + if (len == 0) + end++; #if !ENABLE_EXTRA_COMPAT if (regexec(&gl->compiled_regex, line + end, 1, &gl->matched_range, REG_NOTBOL) != 0) diff --git a/testsuite/grep.tests b/testsuite/grep.tests index 520a1840f..ffce033e6 100755 --- a/testsuite/grep.tests +++ b/testsuite/grep.tests @@ -98,5 +98,9 @@ testing "grep -o does not loop forever" \ 'grep -o "[^/]*$"' \ "test\n" \ "" "/var/test\n" +testing "grep -o does not loop forever on zero-length match" \ + 'grep -o "" | head -n1' \ + "" \ + "" "test\n" exit $FAILCOUNT |