Big Endian vs Little Endian

Data stores in memory split in Bytes

Endianness:Order of bytes (of data) in memory

Big Endian stores Most significant byte First
Little Endian stores Least significant Byte First

Network: Big Endian
PCM: Little Endian
X86: Little Endian
Src:http://www.raywenderlich.com/12910/how-to-make-a-simple-playing-card-game-with-multiplayer-and-bluetooth-part-3/big-endian-vs-little-endian

PHP uninitialized variable evaluation


php > $user;
php > print var_dump(!$user);
PHP Notice: Undefined variable: user in php shell code on line 1
bool(true)
php > print var_dump($user);
PHP Notice: Undefined variable: user in php shell code on line 1
NULL
php > print var_dump(empty($user));
bool(true)




uninialized variable evaluates to NULL (with notice)

!$var evaluates to True

empty($var) evaluates to True

Python String Encoding Conversion (UTF-8/ANSI)

**Python String are recorded in UNICODE internally

Reading file encoded in UTF-8:


with open(fileName,'r') as f:
    for line in f.readlines():
        print line.decode("UTF-8")






Bind bash keyboard shortcut to delete word to slash

add the following line in ~/.bashrc


bind '\C-f:unix-filename-rubout'


Ctrl+F is bound to delete till previous slash

Font Smoothing/Anti-aliasing in Firefox for Windows

Use Firefox Extension "Anti-Aliasing Tuner"

bash_profile vs bashrc vs profile, environment variables

.bash_profile --> login shell

.bashrc --> non-login shell

login shell:
e.g. login via console, ssh

non-login shell:
e.g. new terminal windows in inside GNOME ( already logged in)
/bin/bash in terminal


When bash is invoked as an interactive login shell, or as a non-interac-
tive shell with the --login option, it first reads and executes commands
from the file /etc/profile, if that file exists. After reading that file,
it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that
order, and reads and executes commands from the first one that exists and
is readable. The --noprofile option may be used when the shell is started
to inhibit this behavior.

/etc/profile --> ~/.bash_profile > ~/.bash_login > ~/.profile

Environment Variable

/etc/environment - This file is specifically meant for system-wide environment variable settings. It is not a script file, but rather consists of assignment expressions, one per line. Specifically, this file stores the system-wide locale and path settings.

set -- show environment variables + shell variables

env -- show environment variables

CodeIgniter .htaccess mod_rewrite 404

CodeIgniter directory: /Document-root/[your-URL-path]
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteBase /[your-URL-path]
RewriteCond $1 !^(index\.php)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule (.*)$ index.php/$1 [L]
                  `---!! No heading slash
</IfModule>

Javascript Prototype Chain / Inheritance

*Every Object has an internal link to another object called prototype

Creating an object:

Javascript Core Object ref:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Predefined_Core_Objects

syntax constructs:

var o = {a: 1};

//o ---> Object.prototype ---> null

var a = ["yo", "whadup", "?"];

//a ---> Array.prototype ---> Object.prototype ---> null

function f(){

return 2;

}

//f ---> Function.prototype ---> Object.prototype ---> null

Constructor:

function Graph() {

this.vertexes = [];

this.edges = [];

}

Graph.prototype = {

addVertex: function(v){

this.vertexes.push(v);

}

};

var g = new Graph();

//Graph ---> Graph.prototype ---> Object.prototype

Object.create

var a = {a: 1};

var b = Object.create(a);

// b ---> a ---> Object.prototype ---> null

var c = Object.create(b);

// c ---> b ---> a ---> Object.prototype ---> null

var d = Object.create(null);

// d ---> null

LINUX SYSTEM INITIALIZATION

DEBIAN

1.BIOS
   |--- POST (Power On Self Test)
    `--- Load initial code (bootloader code/kernel code...etc) form DISK
2.Bootloader (Bootstrap Loader)
    `--- load system kernel image and initrd image, hands over control
`-- Linux kernel             `---- initramfs
    * initrd : image of temporary root file system loaded into memory
               do hardware detection,module loading, mnt root file sys
3. initrd (mini-Debian System (Started by bootloader))
`----- /init is executed
4. Debian-System
|----- 0. /sbin/init (init(8)) is executed
| |--- parent of all processes
| `--- create process from script /etc/inittab
|----- 1. System goes into runlevel N(none) by following /etc/inittab
|----- 2. System goes into runlevel S for initialization
`----- 3. System goes into runlevel 2-5(multi-user))(determined by /etc/inittab)
`-- rc.local is executed at the end of each multiuser runlevel

A Bootable Linux Image

Load Sequence: Boot Loader->kernel->initrd->rootfs(the fs user will be working on)




BASIC APACHE

APACHE 2 ON **DEAIBN

#       /etc/apache2/

#       |-- apache2.conf
#       |       `--  ports.conf
#       |-- mods-enabled
#       |       |-- *.load
#       |       `-- *.conf
#       |-- conf.d
#       |       `-- *
#       `-- sites-enabled
#               `-- *


**Struture of config in Debian is different from other linux dist.
** apache2.conf is the main config file
it includes other files (mods-enabled/*, conf.d/*, sites-enabled,ports.conf)

** ports.conf
ports to listen to

Directives: Timeout, Keepalive,AccessFileName ........
Configuration Section Containers:
|
|---evaluted each request : <VirtualHost> <Directory>....
| |
| |--Filesystem cotainer:<Directory> <Files>.....
| |
| `--Webspace Container: <Location>......
|
`---evaluated at startup: <IfDefine> <IfModule> ....
Directives Scoping: Limit the scope of effect of  directives(w/SectionContainer)

.htaccess: Placed in DocumentDirectory, use directives to immediately affect access
Administrator can limit directives in .htaccess by AllowOverride Directive

Virtual Hosting


How apache selects virtual to respond to request
1. Find best matching <VirtualHost> based on IP addr
2. More than 1 match--> compare ServerName and ServerAlias
3. No match found --> handled by global server config


#sites-available/000-example

<VirtualHost *:80>
             `--- Placing IP rather than DN in this directive
        ServerName www.example.org  ß FQDN of server

        ServerAdmin webmaster@localhost  ß admin mail

        DirectoryIndex index.html index.cgi index.pl index.php index.xhtml

                                                                                        `--- index files to look for

        DocumentRoot /var/www           ß root directory of site

        Alias /mydoc /var/local/lib/mydata

        <Directory />

                Options FollowSymLinks

                AllowOverride None

        </Directory>

        <Directory /var/www/>

                Options Indexes FollowSymLinks MultiViews

                                        `----Additional option for Directory

                AllowOverride None

                                        `----.htaccess (Only available under Directory)

                Order allow,deny

                allow from all

                                        |----.Search allow first, then deny, deny overwrites allow

                                        `----Rule not found --> deny

        </Directory>

        ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/  <--CGI Scripts location

        <Directory "/usr/lib/cgi-bin">

                AllowOverride None

                Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch

                               |------ExecCGI à CGI script

                                      |------MultiViews HTTP1.1 content negotiation

                                       `------SymLinksIfOwnerMatch stricter symlink follow

                Order allow,deny

                Allow from all

        </Directory>

        ErrorLog ${APACHE_LOG_DIR}/error.log

        # Possible values include: debug, info, notice, warn, error, crit,

        # alert, emerg.

        LogLevel warn

        CustomLog ${APACHE_LOG_DIR}/access.log combined

</VirtualHost>

<VirtualHost *:80>

    ServerName other.example.com  ßanother virtual host

    ServerAlias other.example.com *.other.example.com

                          `--another way is set ServerAlias

    DocumentRoot /www/otherdomain

</VirtualHost>

<VirtualHost _default_:80>  <--catching request not matching any vhost

    DocumentRoot /www/default

</VirtualHost>

Listen 8080   <--Listen directive should be placed here or in port.conf
Listen 9090

<VirtualHost *:8080 *:9090>  

    DocumentRoot /www/default

</VirtualHost>

UserDir Module

Mods-available/userdir.conf

<IfModule mod_userdir.c>

  UserDir public_html

  UserDir disabled root

  <Directory /home/*/public_html>

    AllowOverride FileInfo AuthConfig Limit

    Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec

  </Directory>

</IfModule>

CGI Dynamic Content w/ PHP,Python,Perl

$apt-get install libapache2-mod-[php,perl,python]

.htaccess

*place directives

<Files ~ "^\.(htaccess|htpasswd)$">

deny from all

</Files>

Option +Indexes –FollowSymLinks

IndexOptions +FancyIndexing

IndexIgnore *.php *.exe

*Rewirte Request URL (Requires mod_rewrite and override allowed)

.htaccess

RewriteEngine on
RewriteBase /myApp         <---- base URL for per-directory rewrites
RewriteCond %{HTTP_HOST}   !^www\.example\.com [NC]
    `----only rewrite when HOST matches(NC flag = no case)

RewriteCond %{HTTP_HOST}   !^$

RewriteCond %{SERVER_PORT} !^80$

RewriteRule ^/?(.*)         http://www.example.com:%{SERVER_PORT}/$1 [L,R,NE]
    |---- $N (0 <= N <= 9) -> back references
    |---- (flag: L -> Stop the rewriting process immediately and don't apply any more rules)
    |---- (flag: R -> Forces an external redirect)

    `----( flag: NE: noescap -> especial characters, such as & and ?, for example, will be converted to their hexcode equivalent. Using the [NE] flag prevents that from happening.)

SQL

login
mysql -hlocalhost -u[username] -p[password]

SELECT DATABASE
use [database]


CREATING USERS/ GRANTING ACCESS TO DATABASE


Create new table:

CREATE table [table name](
id int NOT NULL PRIMARY KEY,
title varchar(255) UNIQUE
.
.
.

);

**NOT NULL
**PRIMARY KEY
**UNIQUE


Insert if not entry not existent or do nothing if entry is duplicate


INSERT INTO table(c1,c2)VALUES(v1,v2) ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id)


Search for duplicate:

SELECT address, count(id) as cnt FROM list
GROUP BY address HAVING cnt > 1


SELECT * FROM all_papers WHERE title IN(SELECT title FROM all_papers WHERE title NOT LIKE  '%unavailable%' GROUP BY (title) HAVING COUNT( title ) >1)

PHP with SQL
$USER = [username];
$PASS = [password];
try {
    $dsn = "mysql:dbname=$DBNAME;host=$HOST";
    $dbh = new PDO($dsn, $USER, $PASS);
    } 
    catch (PDOException $e) {
        print "Error!: " . $e->getMessage();
        die();
    }
    $TABLE = [tablename];
    $sql = "SELECT * FROM $TABLE";
    foreach (self::$dbh->query($sql) as $row) {
        .
        .
        .
    }

use addslashes to process string before INSERT

NFS

NFS user permissions are based on user ID (UID)
a user's access to files is determined by his/her membership of groups on the client, not on the server

Server Side

Packages

nfs-kernel-server
nfs-common
rpcbind

Server Install


apt-get install nfs-kernel-server


NFS Config

Config NFS exports so clients can mount the NFS drive

/etc/export

/home/ 192.168.100.0/24(rw,sync)

tips: Reload export config without restart NFS server

exportfs -a

restart services


/etc/init.d/rpcbind restart
/etc/init.d/nfs-kernel-server restart


Check local NFS config

showmount -e localhost

Client Side

Using autofs to mount NFS drive automatically

apt-get install autofs

File /etc/auto.master

/nfs /etc/auto.nfs

File /etc/auto.nfs

home -rw,fg,soft [IP of NFS server]:/[directory]



Mount with command manually

# mount -t nfs -o proto=tcp,port=2049 nfs-server:/ /mnt

Utililies

showmount

LDAP-NSS-PAM

LDAP
Everything is identified by dn
cn= Common Name
ou= Organizational Unit
dc= Domain Component

Schemas, objectClasses and Attributes

An objectClass is a collection of attributess:

• An objectclass is defined within a Schema
• An objectclass may be a part of an objectclass hierarchy, in which case it inherits all the properties of its parents.
• An objectclass has a globally unique name or identifier

Attributes typically contain data:

• Every attribute is defined in a schema.
• Every attribute is included in one or moreobjectclasses.
• To use an attribute in an entry, itsobjectclass must be included in the entry definition and its objectclass must be included in a schema. In turn, the schema must be identified to the LDAP server.

Install LDAP


apt-get install slapd ldap-utils ldapvi



Config Layout

Setup backend database

Import schemas

$ cd /etc/ldap/schema

$ ldapadd -Y EXTERNAL -H ldapi:/// -f cosine.ldif

$ ldapadd -Y EXTERNAL -H ldapi:/// -f nis.ldif

(Provides linux account attributes)

$ ldapadd -Y EXTERNAL -H ldapi:/// -f inetorgperson.ldif

backend.ldif

# Load dynamic backend modules

dn: cn=module,cn=config

objectClass: olcModuleList

cn: module

olcModulepath: /usr/lib/ldap

olcModuleload: back_hdb.la




# Database Setting

dn: olcDatabase={1}hdb,cn=config

objectClass: olcDatabaseConfig

objectClass: olcHdbConfig

olcDatabase: {1}hdb

olcSuffix: dc=[ID],dc=csie,dc=ntu,dc=edu,dc=tw

olcDbDirectory: /var/lib/ldap

olcRootDN: cn=admin,dc=[ID],dc=csie,dc=ntu,dc=edu,dc=tw

olcRootPW: {SSHA}HUpwPlcpSOwCNd8hRfiQsXFYYdyPewC2**

olcDbConfig: set_cachesize 0 2097152 0

olcDbConfig: set_lk_max_objects 1500

olcDbConfig: set_lk_max_locks 1500

olcDbConfig: set_lk_max_lockers 1500

olcDbIndex: objectClass eq

olcLastMod: TRUE

olcDbCheckpoint: 512 30

olcAccess: to attrs=userPassword,shadowLastChange

  by dn="cn=admin,dc=[ID],dc=csie,dc=ntu,dc=edu,dc=tw" write

  by anonymous auth 

  by self write

  by * none

olcAccess: to attrs=homeDirectory

  by dn="cn=admin,dc=[ID],dc=csie,dc=ntu,dc=edu,dc=tw" write

  by anonymous auth

  by self read

  by * none

olcAccess: to dn.base=""

  by * read

olcAccess: to *

  by dn="cn=admin,dc=fate,dc=csie,dc=ntu,dc=edu,dc=tw" write

  by * read



**note:olcrootPW generated by slappasswd

import backend

ldapadd -v -Y EXTERNAL -H ldapi:/// -f backend.ldif

FRONTEND: Adding users and groups (by ldapscripts or frontend.ldif file)

for /etc/passwd

objectClass: posixAccount
id	uid
password	userPassword
uid	uidNumber
gid	gidNumber
full_name	gecos
Home Directory	homeDirectory
Login shell	loginShell

for /etc/shadow

objectClass: shadowAccount
username	uid
password	userPassword
last	shadowLastChange
may	shadowMin
must	shadowMax
warn	shadowWarning
expire	shadowExpire
disable	shadowInactive
reserved	shadowFlag

for /etc/group

objectClass: posixGroup
group name	cn
password	userPassword
group id	gidNumber
other account	memberUid

option 1: Use ldapscripts to add user

install ldapscripts 
(which includes utilities too add/remove POSIX accounts)
apt-get isntall ldapscripts
modify /etc/ldapscripts/ldapscripts.conf
SERVER=localhost
BINDDN='cn=admin,dc=,dc=csie,dc=ntu,dc=edu,dc=tw'
SUFFIX='dc=,dc=csie,dc=ntu,dc=edu,dc=tw'
GSUFFIX='ou=Groups'
USUFFIX='ou=Peolple'
MSUFFIX='ou=machines'
GIDSTART=10000
UIDSTART=10000
MIDSTART=10000

PASSWORDGEN="pwgen" // $ apt-get install pwgen

RECORDPASSWORDS="yes"

PASSWORDFILE="/var/log/ldapscripts_passwd.log"

BINDPWDFILE="/etc/ldapscripts/ldapscripts.passwd"

keep the rootPW in /etc/ldapscripts/ldapscripts.passwd

sh -c "echo -n '[password]' > /etc/ldapscripts/ldapscripts.passwd"
chmod 400 /etc/ldapscripts/ldapscripts.passwd


**Careful: if authentication failure happens after ldapadduser. Check LDAP database for user password encryption

try dpkg-reconfigure libpam-ldap and set encryption method

Option 2: use frontend.ldif

file frontend.ldif

# Create top-level object in domain
dn: dc=b99902120,dc=csie,dc=ntu,dc=edu,dc=tw
objectClass: top
objectClass: dcObject
objectclass: organization
o: b99902120
dc: b99902120
description: b99902120

#people
dn: ou=people,dc=b99902120,dc=csie,dc=ntu,dc=edu,dc=tw
objectClass: organizationalUnit
ou: people

#groups
dn: ou=groups,dc=b99902120,dc=csie,dc=ntu,dc=edu,dc=tw
objectClass: organizationalUnit
ou: groups

#user setting: ta217, groups, b99902120.csie.ntu.edu.tw
dn: uid=ta217,ou=people,dc=b99902120,dc=csie,dc=ntu,dc=edu,dc=tw
objectClass: inetOrgPerson
objectClass: posixAccount
objectClass: shadowAccount
uid: ta217
displayName: ta217
uidNumber: 1001
gidNumber: 1001
userPassword: SAL2013
gecos: ta217
loginShell: /bin/bash
homeDirectory: /home/ta217
shadowExpire: -1
shadowFlag: 0
shadowWarning: 7
shadowMin: 8
shadowMax: 999999
shadowLastChange: 10877
givenName: 217
sn: ta
cn: ta217
mail: ta217@b99902120.csie.ntu.edu.tw
title: ta217

#group setting: ta217, groups, b99902120.csie.ntu.edu.tw
dn: cn=ta217,ou=groups,dc=b99902120,dc=csie,dc=ntu,dc=edu,dc=tw
objectClass: posixGroup
cn: ta217
gidNumber: 1001


import frontend file
ldapadd -v -x -D -W -f frontend.ldif

nss and pam

apt-get install libpam-ldap libnss-ldap libnss-db nslcd nscd

/etc/libnss-ldap.conf
base dc="dc=b99902120,dc=csie,dc=ntu,dc=edu,dc=tw"
/etc/nsswitch.conf 
passwd: files ldap
group: files ldap
shadow: files ldap
add users and groups
ldapadduser [user] [group]
ldapaddgroup [group]
update pam auth
pam-auth-update
auto create home directory
/etc/pam.d/common-account
session required pam_mkhomedir.so skel=/etc/skel/ umask=0022

Allow user change password
vim /etc/pam.d/common-password
password [success=1 user_unknown=ignore default=die]
pam_ldap.so use_authtok try_first_pass
change to
password [success=1 user_unknown=ignore default=die]
pam_ldap.so try_first_pass




client config

/etc/nslcd.conf

# The user and group nslcd should run as.

uid nslcd

gid nslcd

# The location at which the LDAP server(s) should be reachable.

uri ldap://192.168.50.119

# The search base that will be used for all queries.

base dc=b99902120,dc=csie,dc=ntu,dc=edu,dc=tw

/etc/nsswitch.conf

passwd: files ldap
group: files ldap
shadow: files ldap

iptables / DHCP / network interface

Interface config

/etc/network/interfaces
auto eth0
iface eth0 inet static
address [IP]
netmask [mask]
gateway [gateway(if have one)]

DHCP

Package: DHCP3-server

Select interface for DHCP server

/etc/default/dhcp3-server
INTERFACES="[interface_name]"

DHCP pools

dhcpd.conf
option domain-name "[optional domain-name]"
option domain-name-servers [DNS server IP]

e.g.
subnet 192.168.0.0 netmask 255.255.255.0{
range 192.168.0.1 192.168.0.253;
option routers 192.168.0.254;
option broadcast-address 192.168.0.255;
}

iptables / NAT

#enable ip forwarding

sysctl -w net.ipv4.ip_forward=1

#flush tables

iptables -F -t nat

iptables -F INPUT

iptables -F OUTPUT

iptables -F FORWARD

iptables -P INPUT ACCEPT

iptables -P OUTPUT ACCEPT

iptables -P FORWARD DROP

#NAT

iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -o eth0 -j MASQUERADE

#firewall

iptables -A FORWARD -p icmp -j ACCEPT

iptables -A FORWARD -p udp --sport 53 -j ACCEPT

iptables -A FORWARD -p udp --dport 53 -j ACCEPT

iptables -A FORWARD -p tcp --sport 80 -j ACCEPT

iptables -A FORWARD -p tcp --dport 80 -j ACCEPT

iptables -A FORWARD -p tcp --sport 20:21 -j ACCEPT

iptables -A FORWARD -p tcp --dport 20:21 -j ACCEPT

iptables -A FORWARD -p tcp --sport 23 -j ACCEPT

iptables -A FORWARD -p tcp --dport 23 -j ACCEPT

iptables -A FORWARD -p tcp --sport 110 -j ACCEPT

iptables -A FORWARD -p tcp --dport 110 -j ACCEPT

iptables -A FORWARD -p tcp --sport 25 -j ACCEPT

iptables -A FORWARD -p tcp --dport 25 -j ACCEPT

iptables -A FORWARD -p tcp --sport 995 -j ACCEPT

iptables -A FORWARD -p tcp --dport 995 -j ACCEPT




warning: setlocale LC_ALL

What is LC_ALL:

LC_ALL is the environment variable that overrides all the other localisation settings 

The value 'LC_ALL=C' is essentially an English-only environment that specifies the ANSI C locale.

You'll typically set $LANG to your preference. The individual LC_xxx variables override a certain aspect. LC_ALL overrides them all. The locale command, when called without argument gives a summary of the current settings.

LC_* var priority

LC_ALL > LC_* > LANG

locale def file:

/usr/share/i18n/locales
vi /etc/default/locale

LANG & LANGUAGE

LANG: specifies the default locale for all unset locale variables
LANGUAGE: most programs use this for the language of its interface

warning: setlocale LC_ALL solution

export LC_ALL="en_US.UTF-8" export LANGUAGE="en_US.UTF-8"

KVM-VIRSH

Create a domain

sudo virt-install \
        --name [KVM NAME] \
        --ram=2048 \
        --disk [DRIVE(LVM) IMAGE PATH]\
        --network [bridge=[bridged interface]] \
        --nographics  \  #console only
        --location=http://debian.csie.ntu.edu.tw/debian/dists/testing/main/installer-amd64/ \ #installer location
        --extra-args "console=tty0 console=ttyS0,115200nn8" #extra kernel args, attaching console to VM

Delete a domain

sudo virsh undefine [KVM NAME]

Connect to local VM

virsh list --all
virsh console [VM domain name]


dump config to xml

virsh dumpxml [VM guest name]

error: operation failed: Active console session exists for this domain

virsh console --force [VM domain name]

Git Basics

Settings:

git config --global user.name "username"
git config --global user.email "email"
*to check --> git config --list
*config file : ~/.gitconfig

initial:

ssh-keygen -C "username@email.com" -t rsa
* Generate files to .ssh/, public key paste to Github setting

Initialize A Repo:

mkdir
cd
touch README
git add README
git commit -m 'first commit'

Clone A Repo:

git clone [url] [Target Directory]

Staging/Tracking:

git add

Status:

git status
git diff --> changed but not staged
git diff --cache  --> staged


git status -s  (-s --> short)
(
? ? : untracked
A : new
M : Modified but not added
M  : Modified and added
MM : Modified again after added
 D : deleted project file
)

Commit:

git commit -m "[comment]"
git commit -a --> stage everyfile tracked
git commit --amend --> amend a previeous commmit
Ignore files:
.gitignore

Remove File:

git rm
git rm --cached [file] --> remove from staging area

Move File:

git mv [file_from] [file_to]

Commit History:

git log
git log -p --> show diff
git log -2 --> last 2 commit
git log --stat --> brief
git log --pretty --> foramtting
git log --graph --> branch & merge history

Unmodify:

git checkout -- [file]

Remote:

A remote--> repo stored in other computer

origin --> default remote name

git remote -v --> show remote URLs(for the repo)

git remote add [remote-name] [repo URL]

git fetch [remote-name] --> fetch from remote

git pull [remote-name] --> fetch and merge from remote

git push [remote-name] [local-branch-name] --> push to remote

git remote show [remote-name]

git remote rename [old-name] [new-name]

git remote rm [remote-name]

git tag:

git tag --> show tag in cur. repo

git tag -a [tag] -m [comment] --> annot. tag

git tag -s --> signed tag

git alias:

git config --global alias.[alias] '[command]'

Creating new repo for sync w/ github:

*create repo at github first

 *Push to the remote repo

 e.g.:

 git remote add [remote-name] https://github.com/[username]/[githubrepo] ([remote-name] is user defined)

 git commit -m "first commit"

 git push -u [remote-name] master