README
README.md
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5
6# Shell Script Compiler
7
8A generic shell script compiler. Shc takes a script, which is specified on the command line and produces C source code. The generated source code is then compiled and linked to produce a stripped binary executable.
9
10The compiled binary will still be dependent on the shell specified in the first line of the shell code (i.e shebang) (i.e. #!/bin/sh), thus shc does not create completely independent binaries.
11
12shc itself is not a compiler such as cc, it rather encodes and encrypts a shell script and generates C source code with the added expiration capability. It then uses the system compiler to compile a stripped binary which behaves exactly like the original script. Upon execution, the compiled binary will decrypt and execute the code with the shell -c option.
13
14## Install
15
16```bash
17./configure
18make
19sudo make install
20```
21
22**Note** If `make` fails due to *automake* version, run `./autogen.sh` before running the above commands.
23
24### Ubuntu-specific
25
26```
27sudo add-apt-repository ppa:neurobin/ppa
28sudo apt-get update
29sudo apt-get install shc
30```
31
32If the above installation method seems like too much work, then just download a compiled binary package from [release page](https://github.com/neurobin/shc/releases/latest) and copy the `shc` binary to `/usr/bin` and `shc.1` file to `/usr/share/man/man1`.
33
34## Usage
35
36```
37shc [options]
38shc -f script.sh -o binary
39shc -U -f script.sh -o binary # Untraceable binary (prevent strace, ptrace etc..)
40shc -H -f script.sh -o binary # Untraceable binary, does not require root (only bourne shell (sh) scripts with no parameter)
41```
42
43## The hardening flag -H
44
45This flag is currently in an experimental state and may not work in all systems. This flag only works for **default** shell. For example, if you compile a **bash** script with `-H` flag then the resultant executable will only work in systems where the default shell is **bash**. You may change the default shell which generally is `/bin/sh` which further is just a link to another shell like bash or dash etc.
46
47**Also `-H` does not work with positional parameters (yet)**
48
49## Testing
50
51```bash
52./configure
53make
54make check
55```
56
57## Known limitations
58
59The one (and I hope the only) limitation using shc is the _SC_ARG_MAX system configuration parameter.
60It limits the maximum length of the arguments to the exec function, limiting the maximum length of the runnable script of shc.
61
62!! - CHECK YOUR RESULTS CAREFULLY BEFORE USING - !!
63
64## Links
65
661. [Man Page](http://neurobin.github.io/shc/man.html)
672. [Web Page](http://neurobin.github.io/shc)
68
69# Contributing
70
71If you want to make pull requests, please do so against the **master** branch. The default branch is **release** which should contain clean package files ready to be used.
72
73If you want to edit the manual, please edit the **man.md** file (available in the master branch) instead and then generate the manual file from it with the command (requires `pandoc` to be installed):
74
75```bash
76pandoc -s man.md -t man -o shc.1
77#also run this command to generate the html manual
78pandoc -s man.md -t html -o man.html
79```
80
81If you change anything related to autotools, please run `./autogen.sh` afterwards.
82
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