Error: Expected parameter 'from' not passed to function.

I faced this problem while running Truffle. This error appears as my laptop restarted.

For me the software Parity Ethereum was running and after closing that it works fine

OR

The solution was to restart the testrpc

killall -9 node
testrpc --networkId 5777

and deploying the contract again. If you face the error again delete the json files and run

truffle compile
truffle deploy

MetaMask - RPC Error: Error: Error: [ethjs-rpc] rpc error with payload

The solution is to reset the MetaMask account

Accounts->Settings-> Reset Account

Port not found MAC

I was compiling linphone for IOS and i face this problem while running port command

Solution :

As you install it through the package the path is not updated run these commands and it will be ready to go

Run these commands on terminal

export PATH=$PATH:/opt/local/bin
source .profile
sudo port -v selfupdate

Installing Laravel on Ubuntu 14.04

You need to run these commands

$ sudo apt-get install python-software-properties
$ sudo add-apt-repository ppa:ondrej/php5-oldstable
$ sudo apt-get update
$ sudo apt-get install -y php5 php5-mcrypt

$ sudo apt-get install apache2 libapache2-mod-php5 

$ sudo apt-get install mysql-server php5-mysql

$ curl -sS https://getcomposer.org/installer | php
$ sudo mv composer.phar /usr/local/bin/composer
$ sudo chmod +x /usr/local/bin/composer

$ cd /var/www
$ git clone https://github.com/laravel/laravel.git

$ cd /var/www/laravel
$ sudo composer install

$ sudo chown -R www-data.www-data /var/www/laravel
$ sudo chmod -R 755 /var/www/laravel
$ sudo chmod -R 777 /var/www/laravel/app/storage 

$ sudo vim /etc/apache2/sites-available/laravel.example.conf

Paste this code in laravel.example.conf

<VirtualHost *:80>
        
        ServerName laravel.example.com
        DocumentRoot /var/www/laravel/public

        <Directory />
                Options FollowSymLinks
                AllowOverride None
        </Directory>
        <Directory /var/www/laravel>
                AllowOverride All
        </Directory>

        ErrorLog ${APACHE_LOG_DIR}/error.log
        LogLevel warn
        CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

$ a2ensite laravel.example.conf
$ sudo service apache2 reload 

ERROR: Site laravel.example.com does not exist!

While installing laravel on ubuntu 14.04 i faced this error

ERROR: Site laravel.example.com does not exist!

Solution .

you need to rename the file

cd/etc/apache2/sites-available
sudo mv laravel.example.com laravel.example.conf

sudo a2ensite laravel.example.conf

Laravel Compile issue

While compiling laravel i faced this error

  Problem 1
    - Installation request for laravel/framework v5.0.16 -> satisfiable by laravel/framework[v5.0.16].
    - laravel/framework v5.0.16 requires ext-mcrypt * -> the requested PHP extension mcrypt is missing from your system.

Solution :

 sudo php5enmod mcrypt
 sudo service apache2 restart

Error while installing ROS on ubuntu 12.04

When i run the

sudo apt-get install ros-hydro-desktop-full


i get this error message 

The following packages have unmet dependencies:  ros-hydro-desktop-full : Depends: ros-hydro-desktop but it is not going to be installed                           Depends: ros-hydro-mobile but it is not going to be installed                           Depends: ros-hydro-perception but it is not going to be installed                           Depends: ros-hydro-simulators but it is not going to be installed E: Unable to correct problems, you have held broken packages.

Solution :

sudo aptitude install ros-hydro-desktop-full