Post History

I came up with three methods.


### Exit early

Use `exit` early instead of the `elif` syntax.
Basically shell is an interpreter.
As soon as the parsing of the first `if` statement is finished, it will be executed.
In this case, if shell is bash, `exit` before the parsing of the next `if` statement begins. 

```sh
if [ -n "$BASH_VERSION" ]; then
    for f in *; do echo __BASH__ $f; done
    exit
fi

if [ -n "$ZSH_VERSION" ]; then
    for f (*) echo __ZSH__ $f
fi
```


### Eval string

Use `eval`.

```sh
if [ -n "$BASH_VERSION" ]; then
    for f in *; do echo __BASH__ "$f"; done
elif [ -n "$ZSH_VERSION" ]; then
    eval 'for f (*) echo __ZSH__ "$f"'
fi
```


### Source here-document

This is the same as [Canina's answer](https://linux.codidact.com/posts/285278/285301#answer-285301). However, you can write the code in the same file by using here-document. 

```sh
if [ -n "$BASH_VERSION" ]; then
    for f in *; do echo __BASH__ "$f"; done
elif [ -n "$ZSH_VERSION" ]; then
    source /dev/stdin << '__ZSH_SRC__'
        for f (*) echo __ZSH__ "$f"
__ZSH_SRC__
fi
```