2024-12-09 18:34:15 +00:00
|
|
|
|
---
|
|
|
|
|
|
tags:
|
|
|
|
|
|
- shell
|
|
|
|
|
|
---
|
|
|
|
|
|
|
|
|
|
|
|
# Shell sessions
|
|
|
|
|
|
|
|
|
|
|
|
## **Types of shell session**
|
|
|
|
|
|
|
|
|
|
|
|
Shell sessions can be one of or several instances of the following types:
|
|
|
|
|
|
|
|
|
|
|
|
- **login shell**
|
|
|
|
|
|
- A session that must be authenticated such as when you access remote
|
|
|
|
|
|
resources using SSH
|
|
|
|
|
|
- **non-login shell**
|
|
|
|
|
|
- Not the above
|
|
|
|
|
|
- **interactive shell**
|
|
|
|
|
|
- A shell session that runs in the terminal and thus that the user can
|
|
|
|
|
|
_interact_ with
|
|
|
|
|
|
- **non-interactive shell**
|
|
|
|
|
|
- A shell session that runs without a terminal
|
|
|
|
|
|
|
|
|
|
|
|
If you are working with a remote server you will be in an **interactive login
|
|
|
|
|
|
shell**. If you run a script from the command line you will be in a
|
|
|
|
|
|
**non-interactive non-login shell**.
|
|
|
|
|
|
|
|
|
|
|
|
## Shell sessions and access
|
|
|
|
|
|
|
|
|
|
|
|
The type of shell session that you are currently in affects the
|
2025-01-17 17:56:09 +00:00
|
|
|
|
[environmental and shell variables](static/Environmental-and-shell-variables-04d5ec7e8e2b486a93f002bf686e4bbb)
|
2024-12-09 18:34:15 +00:00
|
|
|
|
that you can access. This is because the order in which configuration files are
|
|
|
|
|
|
read on initialisation differs depending on the type of shell.
|
|
|
|
|
|
|
|
|
|
|
|
- a session defined as a non-login shell will read `/etc/bash.bashrc` and then
|
|
|
|
|
|
the user-specific `~/.bashrc` file to build its environment.
|
|
|
|
|
|
- A session started as a login session will read configuration details from the
|
|
|
|
|
|
`/etc/profile` file first. It will then look for the first login shell
|
|
|
|
|
|
configuration file in the user’s home directory to get user-specific
|
|
|
|
|
|
configuration details.
|
|
|
|
|
|
|
|
|
|
|
|
In Linux, if you want the environmental variable to be accessible from both
|
|
|
|
|
|
login and non-login shells, you must put them in `~/.bashrc`
|
