Technical cheatsheets, etc.
the front page.)
Cheatsheets and the like
Git quick start at
http://git-scm.com/ (which is also the Git home page). (Also, Tumblr user
titusmagnus also has
an example of initializing a remote repository, and
here’s a Git Submodules Cheat Sheet.
(new) is a pretty extensive walkthrough and looks pretty good.
Oh, shit, git! at
http://ohshitgit.com/ is a handy list of solutions to to several common Git oopses.)
- Zack Rusin's excellent Git cheatsheet:
large PNG, and
converted to PDF.
- OpenSSL cheatsheets:
madboa (e.g. STARTTLS testing examples),
bogpeople (certificate inspection),
Samat Jain, SSLShopper’s list of
The Most Common OpenSSL Commands
Have I been pwned? Check whether your account has been compromised, by username
(on any tracked site) or email address. See also their
Pwned Passwords form (but don’t submit any still-valid passwords, of course!).
- There are some good little howtos and a couple tutorials at
encrypt swap, use Kerberos authentication
with Apache and
LVM, and lots more).
Quick IMAP testing cheatsheet (and
local copy). Use this as-is with
telnet, or combine with openssl to test SSL or TLS connections.
- digicert.com also has
an online certificate anaysis tool for SSL websites which can be handy.
- Subversion cheatsheets:
addedbytes' (in PDF and PNG),
- Brad the Mad’s
Exim Cheatsheet is helpful for command-line debugging.
This cheatsheet at
datadisk.co.uk is a bit more extensive. The
madboa cheetsheat above will also be helpful debugging SSL connectiongs,
this SMTP AUTH cheatsheet (not Exim-specific) and
this SMTP command reference.
- Adam Pritchard’s
An interactive Markdown tutorial.
- GPG (GnuPG)
Quick Start at
Mini Howto at
- CSS cheatsheets from
Leslie Franke (HTML) and
addedbytes (PNG and PDF).
How to reset a MySQL(/MariaDB) root password at
MegaCli is an appallingly kludgey and inconsistent tool for working
with LSI MegaRAID controllers (such as those on some Dell PowerEdge
Here’s a cheatsheet showing (for instance) how to bring drives online and set parameters.
Here's a more concise cheatsheet.
tcpdump: The Easy Tutorial and
simple usage of tcpdump.
mdadm cheat sheet at
dave's system administrator reference library. And
here’s another one.
25 example iptables examples from
simple initrd tutorial from
The Command Line Magic Twitter feed (@climagic) is full of clever tips and goodies, mostly one-liners.
Julia Evans has
some ’zines, mostly about Linux debugging and monitoring.
Cool but obscure Unix tools from Kristóf Kovács.
Interactive reference tools
MX Toolbox provides a lot of useful tools for email and network administrators,
such as the ability to check multiple blacklists for your server.
mail-tester.com similarly lets you see how spammy or insecure your mail looks
like to others, but works by having you send it a message, so
it can examine the message as received, rather than just by domain
- On a lighter note,
this Unicode Text Converter
(new) takes ASCII text you provide and grotesquely abuses Unicode
to render it in a bunch of different styles (which you can then
paste into Twitter, your ransom notes, etc.). (Scroll down
past the sample text for a “Small FAQ”.)
intodns.com is an interactive DNS checker with very detailed reports on
the status of your DNS records and nameservers.
- You can check your servers for
the Heartbleed vulnerability (or confirm that you’ve fixed it successfully) at
webatic is “a collection of Web 2.0 free online utilities.” Among
other things, they have
a multi-charset Base64 encoder/decoder (with links to other similar tools for e.g. Quoted-Printable
SenderBase site lets you see what Cisco thinks of your network’s “Web
and Email Reputation”.
Project Honey Pot is a crowdsourced database of IP addresses that appear to have
dipped their muzzles in honeypots.
- Ethernet vendor-prefix lookup tools
from uga.edu (two-way) and
from macvendorlookup.com (batch; can also generate random MAC addresses).
useragentstring.com tells you what your web browser is reporting itself as, and
has reference information (in case, e.g., you need to spoof another
browser or version to make some web site let you in).
Last modified 2018.10.12 by