Nessy's Linux Oneliners
Apache:Rewrite to add www.
Bash essentials:
For Loops
While Loops
If Statement
Remove Comments from file
Comment entire file
Print row if LIKE value
Forensics:
Read data from Hard disk
Hardware:
Physical Memory Modules
Network:
Top connecting IP's
Route outbound connection
PHP:
Linux processlist via PHP
RPM:
Verify file's RPM package
System Monitoring:
Check HDD Percent Used
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Print row if LIKE value
Added On: Tue, 19 Jan 2010 12:30:03 -060 | Visitor Rating: 147 Like It This command will print an entire line if the first column "$1" as the like "42", the $0 represents entire line.
awk '{ if ($1 ~ 42) print $0}' access_log
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Rewrite to add www.
Added On: Tue, 19 Jan 2010 11:37:12 -060 | Visitor Rating: 36 Like It This rewrite rule will check that www. is added to the request and if not add it in.
RewriteEngine on
RewriteCond %{HTTP_HOST} ^domain.com$ [NC]
RewriteRule (.*) http://www.domain.com$1 [L,R=301]
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Check HDD Percent Used
Added On: Wed, 06 Jan 2010 15:52:12 -060 | Visitor Rating: 33 Like It This script can easily be added to a cron job to inform you by email when your server's root filesystem is getting full.
#!/bin/bash
if [ $(/bin/df -h / | tail -n 1 | /bin/awk '{print $5}' | sed 's/%//g') -gt '95' ]
then
/bin/mail -s'Your Drive is over 95% Full' user@domain.com < /dev/null
fi
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Linux processlist via PHP
Added On: Thu, 19 Nov 2009 12:18:20 -060 | Visitor Rating: 27 Like It With this PHP script you can run Linux command and print them nicely to your browser
<?php
echo "<pre><code>";
$process=`ps aux`;
$process1 = str_replace("<", "<", $process);
$process2 = str_replace(">", ">", $process1);
echo $process2;
echo "</code></pre>";
?>
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Comment entire file
Added On: Fri, 11 Sep 2009 09:19:21 -050 | Visitor Rating: 28 Like It With this simple sed command we can easily comment and entire file. sed -i"~" 's/^/#/' FILENAME |
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Route outbound connection
Added On: Tue, 08 Sep 2009 10:32:00 -050 | Visitor Rating: 24 Like It Using this IPTables rule you can route all outbound traffic through one of your addtional IP addresses on your machine, this is useful if one of your IP addresses get blacked listed. iptables -t nat -A POSTROUTING -p tcp --dport 25 -j SNAT --to-source 192.168.1.2 |
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Read data from Hard disk
Added On: Mon, 07 Sep 2009 11:25:48 -050 | Visitor Rating: 26 Like It By reading the raw binary data off the block device of your hard drive we can then pass it through strings and get human readable data. dd if=/dev/sda | strings |
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Physical Memory Modules
Added On: Sun, 06 Sep 2009 18:46:14 -050 | Visitor Rating: 26 Like It This dmidecode command will display how many physical memory slots are available and which have memory installed (along with the size) dmidecode | egrep "Memory Device$" -A8 | egrep "Memory|Size" |
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Remove Comments from file
Added On: Sun, 06 Sep 2009 18:08:00 -050 | Visitor Rating: 24 Like It Removes comments and spaces from a file with regular expressions egrep -v "^#|^$" /etc/httpd/conf/httpd.conf |
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Top connecting IP's
Added On: Sun, 06 Sep 2009 18:08:00 -050 | Visitor Rating: 26 Like It Discover which IP address has the most open TCP sockets to your machine.
netstat -naplt | grep -v LISTEN | awk '{print $5}' | egrep "^[0-9]" | awk -F: '{print $1}' | sort | uniq -c | sort -rnk1
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Verify file's RPM package
Added On: Sun, 06 Sep 2009 18:08:00 -050 | Visitor Rating: 28 Like It Using RPM we are able to verify if a file belongs to a RPM package and that packages name. rpm -qif /etc/httpd/conf/httpd.conf |
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If Statement
Added On: Sun, 06 Sep 2009 18:08:00 -050 | Visitor Rating: 27 Like It If statements are the backbone of all scripting and programing and are very useful to know. if [ '1' == '1' ] ; then echo "Success" ; fi |
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While Loops
Added On: Sun, 06 Sep 2009 18:08:00 -050 | Visitor Rating: 29 Like It Using a while loop we can execute a command as long as the condition is true. while [ '1' == '1' ] ; do echo "Never Ending Loop" ; done |
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For Loops
Added On: Sun, 06 Sep 2009 18:08:00 -050 | Visitor Rating: 28 Like It Using loops we are able to achieve big goals with small commands. for i in `ls` ; do echo $i ; done |