grep: fix -o match with empty string (suggested by Colin Watson <cjwatson@ubuntu.com>)
function old new delta
grep_file 1216 1251 +35
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/findutils/grep.c b/findutils/grep.c
index 688ea6a..024f276 100644
--- a/findutils/grep.c
+++ b/findutils/grep.c
@@ -461,15 +461,19 @@
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)