Setting up a User’s Environment

As referenced in our troubleshooting guide and throughout this document, the recommended way to access most open source tools is by way of using an SSH terminal. This blog entry, although a bit dated, summarizes some of the benefits.

It is not recommended to use a 5250 interface for running open source tools!

This document intends to walk you through the process of initializing environment to use SSH efficiently.

This document also assumes your system administrator has installed the open source toolset on IBM i as documented here.

Step 1: Install an SSH client

There are many free SSH terminal emulators on the market. For the most part, any of these choices will serve you well. Here is a non-exhaustive list of options:

For Windows users:

  • PuTTY

  • Windows Subsystem for Linux (WSL)

  • git bash

  • Cygwin (ensure the “openssh” package is selected during installation)

For Mac/Linux users, the “ssh” command is often already installed. To verify, just open up a terminal window and run:

ssh --version

Step 2: Create your first connection to the system

If using one of the other options, your steps are generally to first open up a terminal window. On Windows, this varies based on which tool you are using. For instance:

  • WSL: press <windows_key>+r and type bash

  • git bash: press <windows_key> and search apps for git bash

  • Cygwin: press <windows_key> and search apps for Cygwin64 Terminal

  • PuTTY: See these steps (external link) for more info.

Once a terminal window is open, connect to the IBM i system with the following command:

ssh user@system

(Of course, replace user with your user profile, and system with the host name or IP address of your IBM i system)

Enter your password as requested. You should now be connected!

Gotcha!!

If your IBM i user profile is longer than 8 characters long, and you are running IBM i 7.3 or earlier, you need to remove this restriction by way of the PASE_USRGRP_LIMITED environment variable. The easy way to do this is to have your system administrator set it system-wide:

ADDENVVAR ENVVAR(PASE_USRGRP_LIMITED) VALUE('N') LEVEL(*SYS)

Step 3: Create your home directory

From your SSH session, run the following command:

mkdir -p $HOME

Now, verify this was successful by running the following commands:

cd $HOME
pwd

The output of the pwd command should match your home directory as configured in your IBM i user profile (typically /home/USRPRF).

Step 4: Change your default shell to bash

The default shell program on IBM i is very deficient as an operating environment. It is highly recommended that you use bash by following these steps, which essentially boils down to running this command in your SSH session:

/QOpenSys/pkgs/bin/chsh -s /QOpenSys/pkgs/bin/bash

(there is also an SQL approach in the docs, if that is preferred)

When complete, exit your SSH session by typing exit and reconnecting as you did earlier. You should now be running bash, as evidenced by a command prompt that indicates a bash version (for instance, -bash-5.1).

Step 5: Configure your PATH

In order for your woking environment to find the open source toolset, you need to set up your PATH (environment variable) appropriately. The PATH is often considered analogous to a library list. Instead of libraries, though, it contains a list of directories to be searched for UNIX-style commands, as would be run in a PASE environment (SSH) on IBM i.

Configuration of PATH is documented in these steps, which boils down to running this sequence of commands in your SSH session:

touch $HOME/.profile
setccsid 1208 $HOME/.profile
echo 'PATH=/QOpenSys/pkgs/bin:$PATH' >> $HOME/.profile
echo 'export PATH' >> $HOME/.profile

When complete, exit your SSH session by typing exit and reconnecting as you did earlier. Your environment should now have PATH set up properly. To verify this, run the following command:

which bash

Output should be:

/QOpenSys/pkgs/bin/yum

Step 6 (optional): Configure password-less login

Would you like to ssh into a system without typing your password? If so, you can use a public/private key pair to authenticate to the system.

Step 6a: Generate a key pair

The first thing you need to do is generate a key pair. PuTTY ships a “PuTTYgen” utility to do this. For other clients, run the following command from your terminal, and respond appropriately to any questions it asks:

ssh-keygen

IMPORTANT NOTE: A key pair consists of a public key and a private key. Never, under any circumstances, share your private key with another entity. It should exist on your local system only.

Step 6b: copy public key to server

Next, you can copy your public key to the IBM i server by running the following command from your terminal:

ssh-copy-id user@host

If, for some reason you don’t have the ssh-copy-id command, or if you used PuTTYgen to generate your key pair, you can manually copy the key to the server. To do so, you can first create the server-side file by running the following:

mkdir -p $HOME/.ssh
touch $HOME/.ssh/authorized_keys

The authorized_keys file will store your public keys for any clients wishing to connect with key-based authentication. After this file is created, you can add your public key. To do so, locate the file on your PC with the public key. This is usually stored in a file named “id_algorithm.pub”, where “algorithm” is the key pair algorithm. Most commonly, the file name is id_rsa.pub. If using PuTTYgen, the user interface shows a text field labeled “public key for pasting into OpenSSH authorized_keys file:”. You can copy/paste that into a file for use with the next step.

Once you’ve located your public key file, you can place it into your home directory on IBM i, open an SSH session and run (substitute file name as needed, this example assumes id_rsa.pub):

cat id_rsa.pub >> $HOME/.ssh/authorized_keys
rm id_rsa.pub

Step 6c: Fix filesystem permissions

OpenSSH strictly enforces that the permissions of the necessary directories and files are set in a secure manner. It will not work unless the permissions are set correctly. To fix them up, run the following commands in your SSH terminal:

chown "$(/QOpenSys/usr/bin/id -u -n)" $HOME
chown -R "$(/QOpenSys/usr/bin/id -u -n)" $HOME/.ssh
chmod 0755 $HOME
chmod 0700 $HOME/.ssh
chmod 0644 $HOME/.ssh/authorized_keys

Step 6d: Verify password-less login

Sign out of your SSH session. Sign on again, as you did before (for instance, ssh user@host). You should now be able to log in without a password!

Having problems?

If you’re having any problems, feel free to reach out to the various community and support resources listed in the IBM i Open Source resources.

Want an even more robust experience?

Check out the dotfiles project, which provides more advanced environment customizations for the IBM i. This is especially useful for Linux users on IBM i.