First there was the command line

First There was the
Command Line
...the first thing that Apple's hackers had done when they'd got the
MacOS up and running--probably even before they'd gotten it up and
running--was to re-create the Unix interface, so that they would be able
to get some useful work done...
-- In the Beginning was the Command Line
Neal Stephenson
http://slidesha.re/1nhg37s

Follow along...
$>mkdir -p ~/www/wp_site/news
&& wget http://wordpress.org/latest.zip
&& unzip latest.zip -d
~/www/wp_site/news
Chaining commands with &
Make news directory under /var/www/wp_site, then
download latest version of WordPress, then extract the
contents of the archive to /var/www/wp_site/news

● Developer at ServerGrove
● All around nerd
● Systems Administrator for
7 years
● @aramonc in all the places
About Me

More than 60% of all web servers use *nix
Why bother?
Debian
Ubuntu
CentOS/RHEL
SmartOS*
Servers do not use graphical interfaces
*Not really Linux, still Unix based

WordPress Powers ~19% of the web
Why bother?
Statistically more likely to be target of attack

● Increased speed & flexibility
● Muscle memory
● Large pool of freely available utilities
● *nix Command Line utilities are mostly
standard
Why bother?

Getting to the Command Line
Windows
Localhost:
Cygwin
Webhost:
SSH via PuTTY
OSX, *nix
Localhost:
Terminal, xterm, etc
Webhost:
SSH via the above

Navigating Folders = Directory Tree

Where are you right now?
$>pwd
/var/www/wp_site
Print Working Directory
● /var/www/wp_site = a path
● / not
● Starts with / (root) = absolute

What’s in here?
$>ls
index.php wp-includes
license.txt wp-links-opml.php
readme.html wp-load.php
wp-activate.php wp-login.php
wp-admin wp-mail.php
wp-blog-header.php wp-settings.php
wp-comments-post.php wp-signup.php
wp-config-sample.php wp-trackback.php
LiSt

What’s in here?
$>ls -la
total 320
drwxr-xr-x 21 adrian_sg wheel 714 Feb 28 22:07 .
drwxr-xr-x 3 root wheel 102 Feb 28 21:57 ..
-rw-r--r--@ 1 adrian_sg wheel 640 Mar 05 20:14 .htaccess
-rw-r--r--@ 1 adrian_sg wheel 418 Sep 24 20:18 index.php
-rw-r--r--@ 1 adrian_sg wheel 19929 Jan 18 2013 license.txt
-rw-r--r--@ 1 adrian_sg wheel 7185 Jan 13 13:16 readme.html
drwxr-xr-x@ 88 adrian_sg wheel 2992 Jan 23 15:17 wp-admin
drwxr-xr-x@ 5 adrian_sg wheel 170 Jan 23 15:17 wp-content
-rw-r--r--@ 1 adrian_sg wheel 2932 Sep 24 20:18 wp-cron.php
LiSt

Moving around...
$>cd wp-admin
$>pwd
/var/www/wp_site/wp-admin
$>cd /var/www/wp_site
$>pwd
/var/www/wp_site
$>cd wp-content/themes/twentyfourteen
$>pwd
/var/www/wp_site/wp-
content/themes/twentyfourteen
Change Directory

Moving around...
$>cd ..
$>pwd
/var/www/wp_site
$>cd ~/
$>pwd
/Users/adrian_sg
$>cd -
$>pwd
/var/www/wp_site
Change Directory

Where is this thing?
$>find . -iname xml*
/var/www/wp_site/xmlrpc.php
$>find . -mtime 3
Find
. (dot) means current directory
-mtime in 24 hour increments of
modified date

$>grep theme ./*
./index.php: * wp-blog-header.php...the theme.
grep: ./wp-admin: Is a directory
./wp-settings.php:require(ABSPATH.WPINC.'/theme.php');
./wp-settings.php:do_action( 'setup_theme' );
Globally search a Regular Expression and Print

$>grep -R theme ./*
./wp-admin/update.php: $parent_file='themes.php';
./wp-admin/update.php: $submenu_file='themes.php';
./wp-admin/update.php: $nonce='install-theme_'.$theme;
Globally search a Regular Expression and Print

Can I change things?
$>ls -l
total 320
-rw-r--r--@ 1 adrian_sg wheel 2932 Sep 24 20:18 wp-cron.php
drwxr-xr-x@ 122 adrian_sg wheel 4148 Jan 23 15:17 wp-includes
-rw-r--r--@ 1 adrian_sg wheel 2359 Oct 24 18:58 wp-load.php
Owners, Groups, & Permissions

Permissions
r = Read
w = Write
x = Execute (run a script or open a directory)
Three levels of permissions: Owner, Group,
Everyone else

Owner = User
● Sometimes your user
● Sometimes root
● Sometimes www-data (Apache user)

Group
● Permissions for a set of users
● Users have own group
● Most users only belong to own group

Permissions
Owner Group EveryoneIs Dir.?
rwx r-x r-xd
$>ls -l
adrian_sg wheel

How do I change this thing?
$>mkdir -p useless/stuff
$>ls -l
drwxr-xr-x 2 adrian_sg wheel 68 Mar 3 22:04 useless
-rw-r--r--@ 1 adrian_sg wheel 4892 Oct 4 10:12 wp-activate.php
MaKe DIRectory

$>mv readme.html useless/stuff/readme
$>ls -l
drwxr-xr-x 2 adrian_sg wheel 68 Mar 3 22:04 useless
-rw-r--r--@ 1 adrian_sg wheel 4892 Oct 4 10:12 wp-activate.php
MoVe

$>cp wp-config-sample.php wp-config.php
$>ls -l
-rw-r--r--@ 1 adrian_sg wheel 4795 Sep 5 21:38 wp-comments-post.php
-rw-r--r--@ 1 adrian_sg wheel 3087 Oct 24 18:58 wp-config-sample.php
-rw-r--r--@ 1 adrian_sg wheel 3087 Mar 3 21:59 wp-config.php
CoPy
● cp -a keeps same permissions
as original

When everything goes wrong...
$>less
/var/log/apache2/error_log
Read the log file

When everything goes wrong...
Read the log file
● (up arrow) to scroll towards the top
● (down arrow) to scroll towards the bottom
● (space) next page
● p previous page
● q(uit) to exit
● / <expression> to search for <expression>
● n to search again

But I only care about the last error...
$>tail -n 5 /var/log/apache2/error_log
[Mon Mar 03 10:28:01 2014] [notice] Digest: generating secret for digest
authentication ...
[Mon Mar 03 10:28:01 2014] [notice] Digest: done
[Mon Mar 03 10:28:01 2014] [notice] Apache/2.2.26 (Unix) DAV/2 PHP/5.5.4
mod_ssl/2.2.26 OpenSSL/0.9.8y configured -- resuming normal operations
[Mon Mar 03 13:40:08 2014] [notice] child pid 8870 exit signal Bus error (10)
[Mon Mar 03 18:02:20 2014] [notice] caught SIGTERM, shutting down
Read the last few lines of the log file

I only care about the current error...
$>tail -f /var/log/apache2/error_log
[Mon Mar 03 10:28:01 2014] [notice] Digest: generating secret for digest
authentication ...
[Mon Mar 03 10:28:01 2014] [notice] Digest: done
[Mon Mar 03 13:40:08 2014] [notice] child pid 8870 exit signal Bus error (10)
[Mon Mar 03 18:02:20 2014] [notice] caught SIGTERM, shutting down
Read the log file as it happens
● -f is interactive
● Ctrl+C to exit interactive

Who is currently on my site?
$>tail -f /var/log/apache2/*access_log
::1 - - [26/Dec/2013:09:35:23 -0500] "OPTIONS * HTTP/1.0" 200 -
127.0.0.1 - - [26/Dec/2013:09:35:34 -0500] "GET / HTTP/1.1" 200 44
127.0.0.1 - - [26/Dec/2013:09:35:34 -0500] "GET /favicon.ico HTTP/1.1" 404 209
127.0.0.1 - - [26/Dec/2013:09:36:40 -0500] "GET / HTTP/1.1" 304 -
127.0.0.1 - - [26/Dec/2013:09:36:42 -0500] "GET / HTTP/1.1" 304 -
Read the access log as it happens

How do I change this thing
$>nano wp-config.php
Nano text editor

How do I change this thing
$>nano wp-config.php
^G Get Help ^O WriteOut
^R Read File ^Y Prev Page
^K Cut Text ^C Cur Pos
^X Exit ^J Justify
^W Where Is ^V Next Page
^U UnCut Text ^T To Spell
Nano text editor

Putting it all together
$>tail -n 10000
/var/log/apache2/error_log | grep “Mar
01” | less
Deep filtering with the pipe statement
Look for any log entry that occurred on March 1st within the
last ten thousand lines of the error log and display it in a
way I can easily navigate

Putting it all together
$>mkdir -p wp-content/uploads && echo -
e "RemoveHandler .php .phtml .php3
php4nRemoveType .php .phtml .php3
php4" > wp-content/uploads/.htaccess
Creating files without a text editor
Make a new uploads directory in wp-content, then create a
.htaccess file in uploads with the contents of
“RemoveHandler .php .phtml .php3 php4
RemoveType .php .phtml .php3 php4”

Resources
● Usage Share of Server OSes
● 162,000 WP Sites Used as Bot Net
● In The Beginning Was the Command Line
● linuxcommand.org
● Command Line Mystery
● 5-Minute Essential Shell Tutorial
● PuTTY
● Cygwin

Thank you!
http://slidesha.re/1nhg37s

First there was the command line

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