Shell Guide¶

Amazing Shell Tips¶

https://www.shell-tips.com/bash/loops/

Interactive Shell¶

https://www.baeldung.com/linux/bash-interactive-prompts

oh my zsh¶

zsh:oh-my-zsh:plugins
docker-compose

Zsh Completions¶

Bash Script Parts¶

Following next naming convention

Info

layout: |-
  ### TOPIC. CHAPTER_NUM__NO_ZEROS. CHAPTER_NAME
terms:
  TOPIC: name id of series. here='Bash Script Parts'
  CHAPTER_NUM__NO_ZEROS: |-
    desc: chapter number in order of entry in script or complexity
    no zeros: to elimitate zero interpretation issues no zeros allowed
  CHAPTER_NAME: name of the chapter sample='Shebang Line'

Bash Script. P11. Shebang Line¶

How does /usr/bin/env work in a Linux shebang line?

!!! question What is shebang

> First line in bash / sh scripts usually looks like

```bash
#!/usr/bin/env python3
```

!!! question How does /usr/bin/env work in a Linux shebang line?

> `_origin_link_` [stack-overflow-question](https://stackoverflow.com/questions/43793040/how-does-usr-bin-env-work-in-a-linux-shebang-line)

`env` is the name of a Unix program. If you read the manual (`man env`) you can see that one way to use it is `env COMMAND`, where in your case, `COMMAND` is `python3`.

According to the manual, this will

> Set each `NAME` to `VALUE` in the environment and run `COMMAND`.

Running env alone will show you what NAMEs and VALUEs are set:

```sh
$ env
TERM=xterm-256color
SHELL=/bin/bash
PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin
```

Therefore, `/usr/bin/env python3` is an instruction to set the `PATH` (as well as all the other `NAME+VALUE` pairs), and then run `python3`, using the first directory in the `PATH` that contains the `python3` executable.

!!! tip Reference - How to use the /usr/bin/env command in a shell script - Why is it better to use "#!/usr/bin/env NAME" instead of "#!/path/to/NAME" as my shebang?

Sdf

sdf sdf

sdf