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@lewisd32
lewisd32 / iptableflip.sh
Created April 15, 2015 18:20
Snippet of Unbounce script for restarting HAProxy with zero downtime
echo "Flipping tables! (╯°□°)╯︵ ┻━┻"
num_rules=3
real=3 # exposed to the ELB as port 443
test=4 # used to install test certs for domain verification
health=5 # used by the ELB healthcheck
blue_prefix=855
green_prefix=866
@jpetitcolas
jpetitcolas / gist:5967887
Created July 10, 2013 16:37
Encode/decode a base64 encoded string in PostGreSQL
-- Decoding
SELECT CONVERT_FROM(DECODE(field, 'BASE64'), 'UTF-8') FROM table;
-- Encoding
SELECT ENCODE(CONVERT_TO(field, 'UTF-8'), 'base64') FROM table;
@bradfitz
bradfitz / diskchecker.pl
Created July 24, 2012 21:05
diskchecker.pl
#!/usr/bin/perl
#
# Brad's el-ghetto do-our-storage-stacks-lie?-script
#
sub usage {
die <<'END';
Usage: diskchecker.pl -s <server[:port]> verify <file>
diskchecker.pl -s <server[:port]> create <file> <size_in_MB>
diskchecker.pl -l [port]
@jboner
jboner / latency.txt
Last active July 3, 2024 14:57
Latency Numbers Every Programmer Should Know
Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference 0.5 ns
Branch mispredict 5 ns
L2 cache reference 7 ns 14x L1 cache
Mutex lock/unlock 25 ns
Main memory reference 100 ns 20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy 3,000 ns 3 us
Send 1K bytes over 1 Gbps network 10,000 ns 10 us
Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD
@hrldcpr
hrldcpr / tree.md
Last active June 8, 2024 18:11
one-line tree in python

One-line Tree in Python

Using Python's built-in defaultdict we can easily define a tree data structure:

def tree(): return defaultdict(tree)

That's it!

@katylava
katylava / git-selective-merge.md
Last active February 27, 2024 10:18
git selective merge

Update 2022: git checkout -p <other-branch> is basically a shortcut for all this.

FYI This was written in 2010, though I guess people still find it useful at least as of 2021. I haven't had to do it ever again, so if it goes out of date I probably won't know.

Example: You have a branch refactor that is quite different from master. You can't merge all of the commits, or even every hunk in any single commit or master will break, but you have made a lot of improvements there that you would like to bring over to master.

Note: This will not preserve the original change authors. Only use if necessary, or if you don't mind losing that information, or if you are only merging your own work.