SSHFS - Mount remote directory through gateway machine

1. Expose target target server ssh port with ssh local port forwarding
   $ ssh -C -N -L localhost:local_port:target:target_ssh_port gateway_user@gateway
2. Mount with sshfs through the port just exposed
   $ sshfs target_user@localhost:/target_directory /mount_point -o port=local_port

Example:

$ ssh -C -N -L localhost:22222:tap-machine:22 tapvpn@company-vpn-host.org

$ sshfs tap@localhost:~/work /mnt/work -o port=22222

Credit: Mounting Filesystems with SSH Forwarding Across a Gateway

Execute one line command on IRB or Rails's console through Unix shell

Basic Unix approach - echo and pipe:

$ echo "<command>" | irb

For example,

$ echo "1 + 1" | irb

1 + 1

2

You can change irb to rails console to execute that command in the Rails environment.

PostgreSQL - export/import schema only

Export

Use -s to specify schema only

pg_dump <src_database_name> -s > schema.sql

(Optional) Use -t to specify table. For more than 1 table just add more -t.

 pg_dump <src_database_name> -s -t <table1_name> -t <table2_name> > schema.sql

Import

psql <dest_database_name> -f schema.sql

Credit:

• How to Import / Export in Postgres Database ?
• How to import existing *.sql files in Postgresql 8.4?
• pg_dump

Allow other people to publish gem to RubyGems

To do that, you need to add them as an owner of that gem with gem owner command.

This is an example

gem owner gem_name -a foo@bar.com

Credit: How to add more 'owners' to a gem in RubyGem

[Solved] Could not open a connection to your authentication agent.

Run this command

eval `ssh-agent`

Credit:  http://www.worldofnubcraft.com/1926/could-not-open-a-connection-to-your-authentication-agent-ssh-add-error/