The following behavior is observed with sed version 4.2.2 (x86_64 / CentOS 7.2).
When I pass a 2GB+-single-line to sed for substitution, sed exits with success status code but it silently fails substitution.
```
$ sed `s/aaa/bbb/g` 20GB+-single-line-file.txt > out.txt && echo OK
OK
(...but nothing gets substituted even though the target string exists)
```
In summary, the cause seems that sed isn't checking error return values from address@hidden
What is happening in detail seems as follows.
At the beginning of `do_subst` function (sed/execute.c),
```
/* The first part of the loop optimizes s/xxx// when xxx is at the
start, and s/xxx$// */
if (!match_regex(sub->regx, line.active, line.length, start,
®s, sub->max_id + 1))
return;
```
`line.length` (unsigned long), is set to the value larger than INT_MAX. And when `match_regex` (sed/regexp.c) calls `re_search`,
```
ret = re_search (®ex->pattern, buf, buflen, buf_start_offset,
buflen - buf_start_offset,
regsize ? regarray : NULL);
```
`buflen` here is equal to `line.length` (the value larger than INT_MAX) but the corresponding argument of `re_search` is `int`. The value is converted to a negative number. Then, `re_search` returns -1 due to its error checking. But the return value is not treated by sed and no errors are raised.
A possible fix could be adding an error checking for `re_search` (like this patch).
Or, we can check if the value of line length exceeds INT_MAX before reaching `re_search`. (`grep` checks it and returns with error status code)
Best regards,