MAmathverse·Dec 30, 2023
Also look at https://github.com/stealth/grab from Sebastian Krahmer.
In Ugrep – a more powerful, fast, user-friendly, compatible grepstealth
grab
C++2014–2023
stealth / grab
grab
experimental and very fast implementation of a grep
3Distinct people
4Mentions
0Explicit recommenders
264GitHub stars
What to know before exploring
What it is
experimental and very fast implementation of a grep
GitHub
Where it is used
No documented product use has been verified yet.
What people are saying
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Also in these discussions
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This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:03:16 PM UTC.
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Mentions over time
HN mentions by year4 dated mentions
Observed mentions: 2014-12-21 22:47:05 UTC to 2023-12-30 21:47:34 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 2 | 1 | 1 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 2 | 1 | 1 |
What Hacker News says
4 sourcesGrab – experimental and fast implementation of grep
2 points · Open discussionI'm the author of ag[1]. File searching stuff interests me, so I took a look at grab. Sadly, grab only compiles on Linux right now. Some of the mmap flags and cpu_set_t aren't defined on OS X. I was curious about the performance claims, so I benchmarked grab and ag on my code directory. Times are medians of five runs. I used a Lenovo X140e running Ubuntu 14.10. It has a 160GB Intel SSD, 8GB of RAM, and an AMD A4-5000 (4 x 1.5Ghz Jaguar).
ggreer@boron:~/code% du -sh .
8.3G .
ggreer@boron:~/code% time ag cpu_set_t
ag cpu_set_t 4.45s user 5.25s system 295% cpu 3.285 total
ggreer@boron:~/code% time grab -R cpu_set_t .
grab -R cpu_set_t . 13.31s user 21.67s system 35% cpu 1:38.28 total
30x faster, but these benchmarks aren't a fair fight. Ag ignores binary and hidden files by default. If I tell ag to do an unrestr
Read the rest
icted search, it's still 2x faster (43 seconds vs 98 seconds). Even with cold caches (echo 3 | sudo tee /proc/sys/vm/drop_caches between each run), ag beats grab handily:
ag -u cpu_set_t 19.62s user 32.56s system 90% cpu 57.433 total
grab -R cpu_set_t . 15.48s user 37.89s system 37% cpu 2:22.67 total
I haven't profiled grab yet, but there's definitely some low-hanging fruit. For example, it looks like grab could get a big speedup by detecting literal patterns and using strstr() instead of a whole PCRE engine. Also, FileGrep::find is calling pthread_mutex_lock/unlock even if there are no matches to print. Adding a condition around that makes grab 1.5x faster.
I'm glad I took a look at grab. Despite its shortcomings, I learned from it. I'll definitely try out a few tricks grab uses that ag doesn't, such as thread affinity.
One more thing: The author of grab is right about counting newlines. It does hurt performance. Still, I enable it by default in ag. I think the tradeoff is worthwhile.
1. https://github.com/ggreer/the_silver_searcher
Edit: The mutex locking change was so straightforward that I submitted a PR: https://github.com/stealth/grab/pull/2
Grab – simple but very fast grep
62 points · Open discussion