L in u X ba sics for h acke rs g e t t I n g s t a r t e d w I t h

Finding the Head
If you just want to view the beginning of a file, you can use the 
head
com-
mand. By default, this command displays the first 10 lines of a file. The 
following command, for instance, shows you the first 10 lines of snort.conf:
kali >head /etc/snort/snort.conf
#-------------------------------------------------
# VRT Rule Packages Snort.conf
#
# For more information visit us at:
--snip--
# Snort bugs:[e-mail]
If you want to see more or fewer than the default 10 lines, enter the 
quantity you want with the dash (
-
) switch after the call to 
head
and before 
the filename. For example, if you want to see the first 20 lines of the file, 
you would enter the command shown at the top of Listing 2-2.

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Text Manipulation
21
kali >head -20 /etc/snort/snort.conf
#-------------------------------------------------
# VRT Rule Packages Snort.conf
#
# For more information visit us at:
--snip--
# Options : --enable-gre --enable-mpls --enable-targetbased
--enable-ppm --enable-perfprofiling enable-zlib --enable-act
live-response --enable-normalizer --enable-reload --enable-react
Listing 2-2: Displaying the first 20 lines of snort.conf in the terminal window
You should see only the first 20 lines of snort.conf displayed in your 
terminal window.
Finding the Tail
The 
tail
command is similar to the 
head
command, but it’s used to view the 
last lines of a file. Let’s use it on snort.conf:
kali >tail /etc/snort/snort.conf
#include $SO_RULE_PATH/smtp.rules
#include $SO_RULE_PATH/specific-threats.rules
#include $SO_RULE_PATH/web-activex.rules
#include $SO_RULE_PATH/web-client.rules
#include $SO_RULE_PATH/web-iis.rules
#include $SO_RULE_PATH/web-miscp.rules
#Event thresholding and suppression commands. See threshold.conf
Notice that this command displays some of the last 
include
lines of the 
rules files, but not all of them, because similar to 
head
, the default for 
tail
is to show 10 lines. You can display more lines by grabbing the last 20 lines 
of snort.conf. As with the 
head
command, you can tell 
tail
how many lines 
to display by entering a dash (
-
) and then the number of lines between the 
command and the filename, as shown in Listing 2-3.
kali >tail -20 /etc/snort/snort.conf
#include $SO_RULE_PATH/chat.rules
#include $SO_RULE_PATH/dos.rules
#include $SO_RULE_PATH/exploit.rules
--snip--
#Event thresholding or suppression commands. See theshold.conf
Listing 2-3: Displaying the last 20 lines of snort.conf in the terminal window
Now we can view nearly all the 
include
lines of the rules files on one 
screen.

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