linuxexpert-practice-labs/labs/linux-plus/1-5-1-shell-environment

Linux+ 1.5.1: The shell environment

A directory of your own on the PATH for good, which startup files bash runs for login and non-login shells, and the history shortcuts.

Before you start

The lab creates user alex (password Lab-Pass-1, shell bash). Do the tasks as alex: sudo -iu alex or su - alex. On the RHEL family alex's login startup file is ~/.bash_profile; on Ubuntu it's ~/.profile.

Tasks

1. Create ~/bin/hi, a script that prints hi from and its own name (echo "hi from $0"), and make it executable. Add $HOME/bin to the front of PATH in alex's login startup file, so that hi works in every new login shell.
2. Add the line echo bashrc ran to ~/.bashrc and echo profile ran to the login startup file. Start bash (non-login) and bash -l (login) and see which lines each one prints. Leave the lines in place until you've run le-lab check, then remove them.
3. Practice history: run ls /etc/ssh, then cd !$, then !!, then press Ctrl+r and type ls to find the first command. Not graded.

Hints

• mkdir -p ~/bin, printf '#!/bin/bash\necho "hi from $0"\n' > ~/bin/hi, chmod +x.
• echo 'export PATH="$HOME/bin:$PATH"' >> ~/.bash_profile (or ~/.profile), then source it; which hi.
• Both families already put ~/bin on the PATH: AlmaLinux's default ~/.bashrc adds it, and Ubuntu's ~/.profile adds it at login if it exists. The export line is how you'd add any other directory.
• bash runs only the first of ~/.bash_profile, ~/.bash_login and ~/.profile that it finds for a login shell.