A guide for beginners

You may have already found a-Shell on the App Store. a-Shell is a terminal emulator for iOS/iPadOS, which allows you to run various Unix commands, from importing the python.rich module to managing vim plugins. You can use ffmpeg, python, lua, tex, perl, clang, wasm, jsc, etc, and edit text using vim or nano-like pico. You can even run JupyterLab; also, code-server may be researched in the future.

What you can do

Basic commands and net commands

As is expected, basic commands like ls, cd and cp are available of course. Many important net commands have been provided as well.

$ ping google.com -c 4
PING google.com (198.18.0.85): 56 data bytes
64 bytes from 198.18.0.85: icmp_seq=0 ttl=64 time=0.406 ms
64 bytes from 198.18.0.85: icmp_seq=1 ttl=64 time=0.454 ms
64 bytes from 198.18.0.85: icmp_seq=2 ttl=64 time=0.532 ms
64 bytes from 198.18.0.85: icmp_seq=3 ttl=64 time=0.396 ms
--- google.com ping statistics ---
4 packets transmitted, 4 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.396/0.447/0.532/0.054 ms

$ nslookup
> apple.com
Server:         198.18.0.2
Address:        198.18.0.2#53
Non-authoritative answer:
Name:   apple.com
Address: 198.18.0.37

man command is also provided, so you can read the manuals of basic commands easily.

Get more packages

A tool called pkg can be used to install some extra commands. You can use pkg install to get more commands:

$ pkg install zip

Use pkg list to list all packages already-installed and pkg search <package name> to search if a package is available. To see all available packages, use pkg search. To remove a package, use pkg remove <package name>.

The variable $PKG_SERVER defines the address to get packages. If the variable is not set, the default repository https://github.c om/holzschu/a-Shell-commands would be used. You can set the repository you use by setting the variable:

$ export PKG_SERVER=https://github.com/holzschu/a-Shell-commands 

If you can’t get or search for any package, there may be something wrong with $PKG_SERVER. Try to unset it to switch to the default repository:

$ unsetenv PKG_SERVER

Edit text files

So far three text editors are provided: vim, pico and ed.

Vim users may be happy to see Vim plugins just work, but plugin managers like vim-plug have many problems. Therefore, it’s suggested to use Vim 8’s built-in package manager. See https://github.com/HeavySnowJakarta/A-guide-to-a-Shell/blob/main/basic-tutorials/basic-tutorials/configure-your-vim.md for details.

If you are not used to Vim and looking for a simpler text editor, pico will suit your needs. GNU Nano under GPL can’t be included in a-Shell due to FSF’s policy, so pico is included to provide a similar experience.

A toy, ed, is also included. ed is a line editor, which allows one to input editing commands line by line. For the example below, r, ,p, 1, 2, 3, 4 and q are commands inside, and others are the outputs by ed.

$ ed
r test.cpp
131
,p
#include<iostream>
using namespace std;
int main(){
        cout << "Hello, world!" << endl;
        int a;
        cin >> a;
        cout << a;
        return 0;
}
1
#include<iostream>
2
using namespace std;
3
4
int main(){
q
$

There are also Web based editors available: Ace, CodeMirror and Monaco. Use pkg to get them installed.

Running codes

See Running codes for tips on running Python, Lua and Perl with a-Shell.

Remote SSH/SFTP

SSH connecting is available. Just use ssh, scp and sftp as you’ve got used to. Use ssh-keygen to generate SSH keys. mosh and sshd are not supported yet.

C/C++ and WebAssembly

Thanks to WebAssembly, it’s not impossible to compile projects written in C/C++. With clang, we can compile C codes into WebAssembly, and with wasm, we can run them easily. In fact, almost all commands installed by pkg are distributed in WebAssembly.