damonparker.org » Snippets

Debugging Wifi Connectivity and Routing

damonp — Fri, 11 Jun 2010 21:33:32 +0000

Sometimes wifi connectivity issues can be massaged a little by getting a little pushy with it… turn your internal airport card off. Leave it off for a minute then turn it back on and see if by forcing it to attempt to re-connect to your local network. Oftentimes this will clear up minor issues.

Check your routing tables:

netstat -nr

Get just the default route:

netstat -nr | grep default

In action:

[root@howie ~]$ netstat -nr | grep default
5:default 192.168.1.1 UGSc 11 5 en1

Enable Sendmail for PHP mail() in OSX

damonp — Thu, 25 Feb 2010 22:05:41 +0000

Since this didn’t dawn on me for thirty minutes while I pursued other avenues…

In /etc/hostconfig add/edit a line like:

MAILSERVER=-YES-

Note to self: Look for more OSX server administration clients.

Apache Log Grepping

damonp — Mon, 14 Sep 2009 18:34:51 +0000

Nothing beats a full stats package, but with a little grepping and a logfile and we can figure out some quick statistics.

Get only hits coming from Google.com/search:

grep 'google.com/search' access_log | head -1

Extract only the referrer field:

grep 'google.com/search' access_log | head -1 | awk '{print $11}'

Get the search terms only:

grep 'google.com/search' access_log | \
head -1 | \
awk '{print $11}' | \
cut -d\? -f2 | cut -d\& -f1 | \
sed 's/+/ /g;s/%22/"/g;s/q=//'

Here’s a little script that puts it all together. It finds the unique search terms, cleans out the trash, sorts them and list the top twenty five in order of descending hit count.

#!/bin/sh
LOG="/var/logs/httpd/access_log"
grep 'google.com/search' $LOG | \
awk '{print $11}' | \
cut -d\? -f2 | cut -d\& -f1 | \
sed 's/+/ /g;s/%22/"/g;s/q=//' | \
sed 's/%[0-9a-fA-F][0-9a-fA-F]/ /g;s/"//g' | \
grep -v '=' | sort | uniq -c | sort -rn | head -25

To see them all remove the | head -25 statement at the end of the command.

Thanks to an article at Linux Journal for the examples.

Find setuid root Files

damonp — Fri, 11 Sep 2009 04:29:20 +0000

Find all setuid / setgid files owned by root:

find / -user root -type f $ -perm -4000 -o -perm -2000 $ -exec ls -ld '{}' \;

Find all setuid / setgid files owned by any user:

find / -type f $ -perm -4000 -o -perm -2000 $ -exec ls -ld '{}' \;

Debugging HTTP Headers with cURL

damonp — Mon, 31 Aug 2009 16:05:39 +0000

curl -I http://damonparker.org

More info on cURL

OSX Scrollbars Top and Bottom

damonp — Mon, 05 Nov 2007 22:00:16 +0000

In Terminal:

defaults write "Apple Global Domain" AppleScrollBarVariant DoubleBoth

Quickly Copy MySQL Database to Remote Host

damonp — Fri, 31 Aug 2007 16:29:50 +0000

Copy an entire database:

mysqldump LOCAL_DBNAME | ssh USER@REMOTE_HOST mysql -p REMOTE_DBNAME

Copy a single table:

mysqldump LOCAL_DBNAME LOCAL_TABLE | ssh USER@REMOTE_HOST -p REMOTE_DBNAME REMOTE_TABLE

This shortcut only works if you can access the local DB without a password. If you have to login to both local and remote MySQL servers, the MySQL password prompts get mashed together. You could specify the password on the command line like

-pPASSWORD

but your shell may keep the password in its history so that anyone with access to your account could pick through your shell history and retrieve the password. Using the MySQL password prompt doesn’t do this.

SSH-Keygen For Public Key Authentication

damonp — Tue, 07 Aug 2007 15:16:09 +0000

ssh-keygen -t dsa -b 1024

[root@titan .ssh]# ssh-keygen -t dsa -b 1024
Generating public/private dsa key pair.
Enter file in which to save the key (/root/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_dsa.
Your public key has been saved in /root/.ssh/id_dsa.pub.
The key fingerprint is:
d2:32:02:4e:25:27:53:8f:c1:ab:80:02:0f:25:da:af root@host.domain.com

Then copy in any public keys into ~/.ssh/authorized_keys

Exim Queue Snippets

damonp — Thu, 28 Jun 2007 13:26:13 +0000

These are all useful when trying to track down an open formmail script.

List bounce messages

exiqgrep -f '^<>$'

Freeze bounce messages

exiqgrep -i -f '^<>$' | xargs exim -Mf

Freeze messages from user@domain.com

exiqgrep -i -f user@domain.com| xargs exim -Mf

Find out what user your webserver runs as. Use this as the email address to key on. For example, my Apache runs as nobody so I want to freeze all messages sent from the user nobody@domain.com so I can look through them to see if I can deduce where the insecure formmail script is.

Delete frozen messages

exiqgrep -z -i | xargs exim -Mrm

Recursive Chmod Tricks

damonp — Wed, 27 Jun 2007 13:03:22 +0000

Recursively chmod only directories

find . -type d -exec chmod 755 {} \;

Similarly, recursively set the execute bit on every directory

chmod -R a+X *

The +X flag sets the execute bit on directories only

Recursively chmod only files

find . -type f -exec chmod 644 {} \;

Recursively chmod only PHP files (with extension .php)

find . -type f -name '*.php' -exec chmod 644 {} \;