What Is a Login Shell? (With Examples)

Understanding the difference between login and non-login shells is essential when configuring your shell environment correctly — especially for tools like pyenv.

Definition

A login shell is a shell session that acts as if you just logged into the system. It reads specific config files like .zprofile or .bash_profile, which are used to set environment variables and paths.

Examples of Login Shells

1. Opening Terminal.app (first window)

• Treated as a login + interactive shell
• Loads: .zprofile and .zshrc

2. SSH into a remote server

ssh user@host

• Loads: .zprofile (Zsh) or .bash_profile (Bash)
• Useful for setting up your environment remotely

3. Explicit login shell using zsh -l

zsh -l

• Loads: .zprofile only
• Good for testing login shell behavior

Not Login Shells

1. Run zsh without -l

zsh

• This is an interactive, but not a login, shell
• Loads: .zshrc only

2. Running a shell script

./myscript.sh

• May invoke a non-login, non-interactive shell
• Doesn’t load .zprofile or .zshrc

Summary Table

But! Why Do People Say .zshrc Doesn’t Run During SSH?

This is a common source of confusion when working with remote servers via SSH.

Typical SSH Session

When you run:

ssh user@host

You get:

• A login shell ✅
• An interactive shell ✅

Result:
Both .zprofile and .zshrc are executed.

When .zshrc Does Not Run

When you run a remote command with SSH, like:

ssh user@host "echo $PATH"

You get:

• A login shell ✅
• But not an interactive shell ❌

Result:

• .zprofile runs ✅
• .zshrc does not run ❌

Summary Table

✅ So yes — in a typical SSH terminal session, .zshrc does run.
❌ But in SSH remote command execution, it does not.

Keep your environment setup in .zprofile, and reserve .zshrc for interactive-only configs like aliases and prompts.

Best Practice

• Put environment setup (like PYENV_ROOT, PATH) in .zprofile
• Put interactive features (like aliases, shell prompts) in .zshrc

This ensures consistent behavior across all terminal types and scripts.