# Linux Config Snippets
- [Bash Customization](#Bash-Customization)
* [Case Insensitive Tab Completion](#Case-Insensitive-Tab-Completion)
- [SSH](#SSH)
* [Setup Remote Access by SSH Key](#Setup-Remote-Access-by-SSH-Key)
## Bash Customization
### Case Insensitive Tab Completion
```sh
echo "set completion-ignore-case on" >> ~/.inputrc
source ~/.bashrc
```
---
## SSH
### Setup Remote Access by SSH Key
1. Create RSA Key Pair
```sh
ssh-keygen
```
> NOTE: If an SSH key already exists you will be prompted to overwrite it - Don't do it
1. Copy the Public Key to the Server
Using the `ssh-copy-id` command if it's available
```sh
ssh-copy-id username@remote_host
```
If the `ssh-copy-id` command isn't available this is an alternative
```sh
cat ~/.ssh/id_rsa.pub | ssh username@remote_host "mkdir -p ~/.ssh && touch ~/.ssh/authorized_keys && chmod -R go= ~/.ssh && cat >> ~/.ssh/authorized_keys"
```
1. Authenticate to the Server Using SSH Keys
```sh
ssh username@remote_host
```
1. Disable Password Authentication on the Server (Optional)
Edit the `/etc/ssh/sshd_config` file and Add the following line (or update it if it exists)
```
...
PasswordAuthentication no
...
```
Save the file and restart the `ssh` service by running
```sh
sudo systemctl restart ssh
```
> Before closing the terminal check that you are able to login from another terminal to avoid getting locked out
<IfModule mod_headers.c>
#cache CSS, JavaScript and text files for one week
<FilesMatch "\.(js|css)$">
Header set Cache-Control "max-age=604800"
</FilesMatch>
</IfModule>
Solid Base .htaccess为.htaccess文件创建可靠的基础。目前包括RewriteBase，Security（针对索引，文件等）和Expires Headers（缓存，性能）。
.00 Solid Base .htaccess.md
# Solid Base .htaccess
Creating a solid base for your `.htaccess` file. Currently includes RewriteBase, Security (against indexes, files, etc.), and Expires Headers (caching, performance).
* The URL REWRITES would go at the top of the file.
* The SECURITY and the WEB PERFORMANCE can go towards the bottom... before and WordPress or WP Super Cache items.
* UPDATE 2013-08-21: Added code for forcing either non-www or www. on URLs. Also added the MultiViews option.
* UPDATE 2013-08-23: Added specific code for `wp-config.php`
* UPDATE 2013-10-04: Increased favicon expire time.
* UPDATE 2014-02-05: Removed the Force URL rewrites since there's more than one option.
* UPDATE 2014-12-10: Updated Expires Headers
* UPDATE 2015-04-10: Updated file security
.htaccess
# ######################################################################
# # SECURITY #
# ######################################################################
# ----------------------------------------------------------------------
# | File access |
# ----------------------------------------------------------------------
# Block access to directories without a default document.
# Usually you should leave this uncommented because you shouldn't allow anyone
# to surf through every directory on your server (which may includes rather
# private places like the CMS's directories).
<IfModule mod_autoindex.c>
Options -Indexes
</IfModule>
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Block access to hidden files and directories.
# This includes directories used by version control systems such as Git and SVN.
<IfModule mod_rewrite.c>
RewriteCond %{SCRIPT_FILENAME} -d [OR]
RewriteCond %{SCRIPT_FILENAME} -f
RewriteRule "(^|/)\." - [F]
</IfModule>
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Block access to backup and source files.
# These files may be left by some text editors and can pose a great security
# danger when anyone has access to them.
<FilesMatch "(^#.*#|\.(bak|config|dist|fla|inc|ini|log|psd|sh|sql|sw[op])|~)$">
Order allow,deny
Deny from all
Satisfy All
</FilesMatch>
# Rules to block access to WordPress specific files
<files readme.html>
Order allow,deny
Deny from all
</files>
<files readme.txt>
Order allow,deny
Deny from all
</files>
<files README.md>
Order allow,deny
Deny from all
</files>
<files install.php>
Order allow,deny
Deny from all
</files>
<files wp-config.php>
Order allow,deny
Deny from all
</files>
# Rules to disable XML-RPC
<files xmlrpc.php>
Order allow,deny
Deny from all
</files>
# Deny access to all .htaccess files
<files ~ "^.*\.([Hh][Tt][Aa])">
order allow,deny
deny from all
satisfy all
</files>
<IfModule mod_rewrite.c>
RewriteEngine On
# Rules to protect wp-includes
RewriteRule ^wp-admin/includes/ - [F]
RewriteRule !^wp-includes/ - [S=3]
RewriteCond %{SCRIPT_FILENAME} !^(.*)wp-includes/ms-files.php
RewriteRule ^wp-includes/[^/]+\.php$ - [F]
RewriteRule ^wp-includes/js/tinymce/langs/.+\.php - [F]
RewriteRule ^wp-includes/theme-compat/ - [F]
# Rules to prevent php execution in uploads
RewriteRule ^(.*)/uploads/(.*).php(.?) - [F]
# Rules to block unneeded HTTP methods
RewriteCond %{REQUEST_METHOD} ^(TRACE|DELETE|TRACK) [NC]
RewriteRule ^(.*)$ - [F]
# Rules to block foreign characters in URLs
RewriteCond %{QUERY_STRING} ^.*(%0|%A|%B|%C|%D|%E|%F).* [NC]
RewriteRule ^(.*)$ - [F]
# Rules to help reduce spam
RewriteCond %{REQUEST_METHOD} POST
RewriteCond %{REQUEST_URI} ^(.*)wp-comments-post\.php*
RewriteCond %{HTTP_REFERER} !^(.*)CHANGETHENAMEOFYOURWEBSITEHERE.com.*
RewriteCond %{HTTP_REFERER} !^http://jetpack\.wordpress\.com/jetpack-comment/ [OR]
RewriteCond %{HTTP_USER_AGENT} ^$
RewriteRule ^(.*)$ - [F]
</IfModule>
# ######################################################################
# # WEB PERFORMANCE #
# ######################################################################
# ----------------------------------------------------------------------
# | Compression |
# ----------------------------------------------------------------------
<IfModule mod_deflate.c>
# Force compression for mangled `Accept-Encoding` request headers
# https://developer.yahoo.com/blogs/ydn/pushing-beyond-gzipping-25601.html
<IfModule mod_setenvif.c>
<IfModule mod_headers.c>
SetEnvIfNoCase ^(Accept-EncodXng|X-cept-Encoding|X{15}|~{15}|-{15})$ ^((gzip|deflate)\s*,?\s*)+|[X~-]{4,13}$ HAVE_Accept-Encoding
RequestHeader append Accept-Encoding "gzip,deflate" env=HAVE_Accept-Encoding
</IfModule>
</IfModule>
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Compress all output labeled with one of the following media types.
#
# (!) For Apache versions below version 2.3.7 you don't need to
# enable `mod_filter` and can remove the `<IfModule mod_filter.c>`
# and `</IfModule>` lines as `AddOutputFilterByType` is still in
# the core directives.
#
# https://httpd.apache.org/docs/current/mod/mod_filter.html#addoutputfilterbytype
<IfModule mod_filter.c>
AddOutputFilterByType DEFLATE "application/atom+xml" \
"application/javascript" \
"application/json" \
"application/ld+json" \
"application/manifest+json" \
"application/rdf+xml" \
"application/rss+xml" \
"application/schema+json" \
"application/vnd.geo+json" \
"application/vnd.ms-fontobject" \
"application/x-font-ttf" \
"application/x-javascript" \
"application/x-web-app-manifest+json" \
"application/xhtml+xml" \
"application/xml" \
"font/eot" \
"font/opentype" \
"image/bmp" \
"image/svg+xml" \
"image/vnd.microsoft.icon" \
"image/x-icon" \
"text/cache-manifest" \
"text/css" \
"text/html" \
"text/javascript" \
"text/plain" \
"text/vcard" \
"text/vnd.rim.location.xloc" \
"text/vtt" \
"text/x-component" \
"text/x-cross-domain-policy" \
"text/xml"
</IfModule>
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Map the following filename extensions to the specified
# encoding type in order to make Apache serve the file types
# with the appropriate `Content-Encoding` response header
# (do note that this will NOT make Apache compress them!).
#
# If these files types would be served without an appropriate
# `Content-Enable` response header, client applications (e.g.:
# browsers) wouldn't know that they first need to uncompress
# the response, and thus, wouldn't be able to understand the
# content.
#
# https://httpd.apache.org/docs/current/mod/mod_mime.html#addencoding
<IfModule mod_mime.c>
AddEncoding gzip svgz
</IfModule>
</IfModule>
# ----------------------------------------------------------------------
# | ETags |
# ----------------------------------------------------------------------
# Remove `ETags` as resources are sent with far-future expires headers.
#
# https://developer.yahoo.com/performance/rules.html#etags
# https://tools.ietf.org/html/rfc7232#section-2.3
# `FileETag None` doesn't work in all cases.
<IfModule mod_headers.c>
Header unset ETag
</IfModule>
FileETag None
# ----------------------------------------------------------------------
# | Expires headers |
# ----------------------------------------------------------------------
# Serve resources with far-future expires headers.
#
# (!) If you don't control versioning with filename-based
# cache busting, you should consider lowering the cache times
# to something like one week.
#
# https://httpd.apache.org/docs/current/mod/mod_expires.html
<IfModule mod_expires.c>
ExpiresActive on
ExpiresDefault "access plus 1 month"
# CSS
ExpiresByType text/css "access plus 1 year"
# Data interchange
ExpiresByType application/atom+xml "access plus 1 hour"
ExpiresByType application/rdf+xml "access plus 1 hour"
ExpiresByType application/rss+xml "access plus 1 hour"
ExpiresByType application/json "access plus 0 seconds"
ExpiresByType application/ld+json "access plus 0 seconds"
ExpiresByType application/schema+json "access plus 0 seconds"
ExpiresByType application/vnd.geo+json "access plus 0 seconds"
ExpiresByType application/xml "access plus 0 seconds"
ExpiresByType text/xml "access plus 0 seconds"
# Favicon (cannot be renamed!) and cursor images
ExpiresByType image/vnd.microsoft.icon "access plus 1 year"
ExpiresByType image/x-icon "access plus 1 year"
# HTML
ExpiresByType text/html "access plus 0 seconds"
# JavaScript
ExpiresByType application/javascript "access plus 1 year"
ExpiresByType application/x-javascript "access plus 1 year"
ExpiresByType text/javascript "access plus 1 year"
# Manifest files
ExpiresByType application/manifest+json "access plus 1 year"
ExpiresByType application/x-web-app-manifest+json "access plus 0 seconds"
ExpiresByType text/cache-manifest "access plus 0 seconds"
# Media files
ExpiresByType audio/ogg "access plus 1 month"
ExpiresByType image/bmp "access plus 1 month"
ExpiresByType image/gif "access plus 1 month"
ExpiresByType image/jpeg "access plus 1 month"
ExpiresByType image/png "access plus 1 month"
ExpiresByType image/svg+xml "access plus 1 month"
ExpiresByType video/mp4 "access plus 1 month"
ExpiresByType video/ogg "access plus 1 month"
ExpiresByType video/webm "access plus 1 month"
# Web fonts
# Embedded OpenType (EOT)
ExpiresByType application/vnd.ms-fontobject "access plus 1 year"
ExpiresByType font/eot "access plus 1 year"
# OpenType
ExpiresByType font/opentype "access plus 1 year"
# TrueType
ExpiresByType application/x-font-ttf "access plus 1 year"
# Web Open Font Format (WOFF) 1.0
ExpiresByType application/font-woff "access plus 1 year"
ExpiresByType application/x-font-woff "access plus 1 year"
ExpiresByType font/woff "access plus 1 year"
# Web Open Font Format (WOFF) 2.0
ExpiresByType application/font-woff2 "access plus 1 year"
# Other
ExpiresByType text/x-cross-domain-policy "access plus 1 week"
</IfModule>