Quick Notes
This page is to list all of those quick, often one-line, commands or hints that help during the course of system administration.
Contents |
VoIP
Links
Networking
- Network Overhead Guide
- To capture packets for wireshark/ethereal, run tcpdump as: tcpdump -i <interface> -s 1500 -w <some-file>
MediaWiki Notes
This section is for all the stuff you can do or need to do with Media Wiki that isn't found in an easy location.
You can edit the links under navigation, etc, on the left of the page by going to a special page in MediaWiki. <host>/wiki/index.php/MediaWiki:Sidebar will take you there. You can see the SCN side bar at MediaWiki:Sidebar.
VIM
Command Line Foo
- Interface statisctics without iftop from ports: systat -if
with csh/tcsh, |& pipes both stdout and stderr. same effect as 2>&1 | in bourne-based shells (or /bin/sh)
Make this command an alias to tree in your .<shell>rc and get that ol' DOS-style tree:
find . -print | sed -e 's;[^/]*/;|____;g;s;____|; |;g'
Here's a nice command to use in conjunction with GeekTool for current weather conditions on your desktop:
curl --silent "http://xml.weather.yahoo.com/forecastrss?p=YOURCITYCODE&u=c" | grep -E '(Current Conditions:|C<BR)' | sed -e 's/Current Conditions://' -e 's/<br \/>//' -e 's/<b>//' -e 's/<\/b>//' -e 's/<BR \/>//' -e 's/<description>//' -e 's/<\/description>//'
Note: change YOURCITYCODE with your zip code.
iPhone Notes
Windows Notes
- Windows XP WPA2 Support WinXP WPA2
SpamAssassin
Postfix
http://www.freesoftwaremagazine.com/articles/secure_email_servers_from_scratch_with_freebsd_6_part_2
vMail.Admin
Link sudo to /usr/bin/sudo
# ln -s /usr/local/bin/sudo /usr/bin/sudo
Firefox
- No Scroll Tabs: goto about:config, set browser.tabs.tabMinWidth=1
- Close on Tab: goto about:config, set browser.tabs.closeButtons=1
PostgreSQL
- Postgres does not authenticate users as MySQL, and doesn't offer a shell.
- When connecting to Postgres dbs, you must specify the db, otherwise a db names as the role will be assumed.
Basic Commands
- psql -l (dash el): list databases
- pg_dumpall: dump all dbs to stdout
- gzipped use: pg_dumpall | gzip -c > all.dbs.out.gz
- restore: gzcat all.dbs.out.gz | psql -f - postgres
MySQL Stuff
Command/Query Examples
| Description | Command | Notes |
|---|---|---|
| Forcibly change a user's password. | SET PASSWORD FOR user=PASSWORD('password'); | |
| Add New Database User | GRANT ALL PRIVILEGES ON db.table to 'user'@'host' IDENTIFIED BY 'password'; | You can use a % to denote ANY host. The percent (%) purposely excludes localhost, however. |
| Copy rows from one table to another. | INSERT INTO foo SELECT * FROM bar; | copies records from table bar into table foo. |
| action based on time interval | SELECT FROM foo WHERE DATE(field) < (YYYYMMDD - INTERVAL nnn unit) | Where unit = DAY/YEAR/MONTH - one of those, will select based on records older than the interval. |
| Flush all queries from the cache. | FLUSH QUERY CACHE |
This command can be used to dump all databases on the current system to another system, piping the content through an SSH session:
mysqldump -u USERNAME -pPASSWORD --opt --compress --all-databases | ssh REMOTEHOST "cat - | mysql -u USERNAME -pPASSWORD"
Links
Apple Remote Desktop 3.1
This is just a place-holder.
GNU Screen
A nice .screenrc config file:
This config works well on both light and dark colored backgrounds.
startup_message off
shelltitle ''
defmonitor on
vbell off
hardstatus on
hardstatus alwayslastline
hardstatus string '%{= bW}%-Lw%{= rW}%50>%n%f %t%{= bW}%+Lw%< %-= %{..Y}%m/%d %c:%s%{-}'
Here's another .screenrc config, from Jeremy O'Brien (piroko):
This config works well on dark colored backgrounds.
shelltitle ''
startup_message off
vbell off
defmonitor on
monitor on
caption always "%{= kw}> %{y}%?%-Lw%?%{w}(%{R}%n*%t%?(%u)%?%{w})%{y}%?%+Lw%?%?%=%{w} [ %{.c}%M %d%{y}%0c:%s%{w} ]"
Screen after su
sudo su - <user> script /dev/null screen (or screen -r)
Links
PHP
| Function | Code Example | Description |
|---|---|---|
| foreach | foreach ($array as $key => $value) { code } | |
Example for output files with support for multipart downloading:
if (isset($_SERVER['HTTP_RANGE'])){
list($a, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
list($range) = explode(',', $range, 2);
list($range, $rangeEnd) = explode('-', $range);
$range = intval($range);
if (!$rangeEnd){
$rangeEnd = $fileSize -1;
} else {
$rangeEnd = intval($rangeEnd);
}
$newLength = $rangeEnd - $range + 1;
// Send Headers
header("Content-Type: applicatoin/zip");
header("Content-Length: $size");
header("Content-Range: bytes " . $range - $rangeEnd / $size);
} else {
$newLength = $size;
header('Content-Length: ' . $size);
}
IRSSI
- [1] - good how to for screen + irssi
RegEx (Regular Expressions)
| REGEX | What it does. |
|---|---|
| /^$|^\d{5}(-?\d{4})?$|^[ABCEGHJKLMNPRSTVWXYZ]\d[ABCEGHJKLMNPRSTVWXYZ](\s?)\d[ABCEGHJKLMNPRSTVWXYZ]\d/i | Validates for blank string, US zipcode (either 5 digit or 5+4, and Canadian postal codes (with or without a space). |
Samsung Vibrant/Galaxy S
- LBS/GPS Test Mode: *#*#1472365#*#* SEND