# Introduction

Cicada is a simple bash-like Unix shell.

### Try out cicada with Docker

```
$ docker pull mitnk/cicada
$ docker run --rm -it mitnk/cicada
(in-cicada) $ cinfo
```

## Basic cicada Features

### Run programs and pipelines

```
$ ls | head -n3
Desktop
Documents
Downloads

$ echo foo,bar | awk -F "," '{print $2, $1}'
bar foo
```

### With redirections

```
$ ls file-not-exist 2>&1 | wc > e.txt
$ cat e.txt
       1       7      46

$ cat <<< 'here string'
here string
```

### Command substitution

```
$ ls -l `which sh`
-r-xr-xr-x  1 root  wheel  618512 Oct 26  2017 /bin/sh

$ echo "Time is $(date)."
Time is Sun Sep  2 12:04:13 CST 2018.
```

### Run multiple commands (with logical)

```
$ echo foo; echo bar
foo
bar

$ echo foo && echo bar
foo
bar

$ echo foo || echo bar
foo
```

### Shell expansions

```
$ echo sp{el,il,al}l
spell spill spall

$ echo $SHELL
/usr/local/bin/cicada

$ echo *
Cargo.lock Cargo.toml LICENSE Makefile README.md src target
```

### Math arithmetic directly in the shell!

```
$ 1 + 2 * 3 - 4
3
$ (1 + 2) * (3 - 4) / 8.0
-0.375
$ 2 ^ 31
2147483648
```