Installing Mecurial on Ubuntu (2013 Archive)

Mercurial is a free, distributed source control management tool. It efficiently handles projects of any size and offers an easy and intuitive interface.

Note: after each line of code you type in - you need to hit the enter key.

Step 1: Install Merucurial and Dependencies

You need to Install .ssh to communicate with the MIT server in order to clone and communicate with the shared archive. Type:

Step 2: Key files

You need to put key files (academy and where Mercurial can find them.

Open terminal

You will be in your home directory by default. Your prompt with look like:


Where "YourUsername" is the username you created to login to Ubuntu.

Type the following text into the terminal after the prompt:

sudo ls ~/.ssh  

You system will ask you for a password - type in the password you use to log in to Ubuntu.

Note: If the system responds with a message like: ls: cannot access /home/akaziuna/.ssh: No such file or directory, then you need to create the .ssh folder. If you do not get this message, skip the command below.


sudo mkdir ~/.ssh        

Within the .ssh directory you need to create another directory called keys. To do this type:

sudo mkdir ~/.ssh/keys

Download the keys that your instructor sent you in an email. They are named academy and You will need to place them in the keys directory. To do this, save the key files to your desktop from the email.

Change your location in the terminal by moving to the Desktop folder.


cd ~/Desktop

Your prompt should now look like: YourUsername@ubuntu:~/Desktop$

You need to move both of the keys from your desktop to the keys directory that you created earlier.


sudo mv academy ~/.ssh/keys
Then type:
sudo mv ~/.ssh/keys

Both keys are now located in the .ssh directory. You can check to see by typing: sudo ls -l ~/.ssh/keys to list the contents of the directory. You should see that academy and are listed.

Step 3: Permissions for the Private Key

You need to set permissions for your private key so that only you have read/write access to them.


sudo chmod go-rw ~/.ssh/keys/academy
Then type:
sudo chmod go-rw-r--r-- ~/.ssh/keys/

Step 4: Setting the Port

You will need to set the port that ssh uses to access You can do this by creating and editing a config file within your .ssh directory.


touch config

A file named config has been created on the desktop. Now we need to edit the file. This file should not have any extension.


sudo gedit config        

A text editor will open outside of terminal.. Add the following text to the text editor in the terminal window:

port 846 

Save the file. Do not add any extension to the file.

Now we need to move it to the .ssh directory.


sudo mv config ~/.ssh/keys

Step 5: Clone the archive

Now we need to clone the archive. For convenience, we will clone it to the desktop.

Copy the text and paste it into the terminal:

hg clone -e "ssh -p 846 -i ~/.ssh/keys/academy" ssh:// academy.2013

You should see the following response from the terminal as the archive is cloned. Success!

        requesting all changes
           adding changesets
           adding manifests
           adding file changes
           added 50 changesets with 141 changes to 101 files
           updating to branch default
           89 files updated, 0 files merged, 0 files removed, 0 files unresolved
           remote: buffer_get_ret: trying to get more bytes 4 than in buffer 0
           remote: buffer_get_string_ret: cannot extract length
           remote: key_from_blob: can't read key type
           remote: key_read: key_from_blob 
           remote:  failed  
Note: The number of files listed varies with the number of files in archive. A folder named academy.2013 has been created on your desktop. This folder contains the archive.

Step 6: Edit the Configuration File

Now you need to edit your archive's personal configuration file. To do this you need to move into the archive folder that you just created on the desktop. It is called academy.2013


cd academy.2013

You are now within the academy.2013 directory. Your path should change to : YourUsername@ubuntu:~/Desktop/academy.2013$

To edit your archive's personal configuration file (called hgrc) to reflect your name and email we need to open the file in a editior:


sudo gedit .hg/hgrc

A text editor will open outside of the terminal window. This text should already be in the file:

default = ssh://

Note: Do not change this text, just add to it - see step 5.

Put the following text in the file. Change the First and Last Name to your first and last name. Change the "<user@machine.domain>" text to your email address. Save the file. Do not add an extension.

username = First Last <user@machine.domain>
ssh = ssh -p 846 -i ~/.ssh/keys/academy -C
changegroup = hg update >&2

Step 7: Update Your Archive

Now try updating your archive by typing:

hg pull

you should see a response like this:

searching for changes
           no changes found
           remote: buffer_get_ret: trying to get more bytes 4 than in buffer 0
           remote: buffer_get_string_ret: cannot extract length
           remote: key_from_blob: can't read key type
           remote: key_read: key_from_blob 
         remote:  failed

If you are asked for a password, then Mecurial can't find the keys or the key file permissions are wrong. (see steps 2 & 3).

If it says something about port 22, then you forgot to update the config file. (see step 4)

Working With Mercurial

To get all changes from the MIT repository into your repository:

hg pull

To add new files

hg add

To commit changes

hg commit -m 'MESSAGE'

To push files to server - Never force push!

hg push

Having Problems? Getting Strange Error Messages? - See:

Mercurial Troubleshooting

Tutorial by Anna Kaziunas France - Fab Academy AS220 Providence, RI - March 2012