30 lines
1.5 KiB
Markdown
30 lines
1.5 KiB
Markdown
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---
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tags:
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- Programming_Languages
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- shell
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---
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## **Types of shell session**
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Shell sessions can be one of or several instances of the following types:
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* **login shell**
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* A session that must be authenticated such as when you access remote resources using SSH
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* **non-login shell**
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* Not the above
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* **interactive shell**
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* A shell session that runs in the terminal and thus that the user can *interact* with
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* **non-interactive shell**
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* A shell session that runs without a terminal
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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**.
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## Shell sessions and access
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The type of shell session that you are currently in affects the [environmental and shell variables](https://www.notion.so/Environmental-and-shell-variables-04d5ec7e8e2b486a93f002bf686e4bbb) that you can access. This is because the order in which configuration files are read on initialisation differs depending on the type of shell.
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* a session defined as a non-login shell will read `/etc/bash.bashrc` and then the user-specific `~/.bashrc` file to build its environment.
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* 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.
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In Linux, if you want the environmental variable to be accessible from both login and non-login shells, you must put them in `~/.bashrc`
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