shc(1)shc(1)NAMEshc - Generic shell script compiler
SYNOPSISshc [ -e date ] [ -m addr ] [ -i iopt ] [ -x cmnd ]
[ -l lopt ] [ -ACDhTv ] -f script
DESCRIPTIONshc creates a stripped binary executable version of the script speci‐
fied with -f on the command line.
The binary version will get a .x extension appended and will usually be
a bit larger in size than the original ascii code. Generated C source
code is saved in a file with the extension .x.c
If you supply an expiration date with the -e option the compiled binary
will refuse to run after the date specified. The message "Please con‐
tact your provider" will be displayed instead. This message can be
changed with the -m option.
You can compile any kind of shell script, but you need to supply valid
-i, -x and -l options.
The compiled binary will still be dependent on the shell specified in
the first line of the shell code (i.e. #!/bin/sh), thus shc does not
create completely independent binaries.
shc 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. Unfortunatelly, it will not give you any speed improvement as
a real C program would.
shc's main purpose is to protect your shell scripts from modification
or inspection. You can use it if you wish to distribute your scripts
but don't want them to be easily readable by other people.
OPTIONS
The command line options are:
-e date
Expiration date in dd/mm/yyyy format [none]
-m message
message to display upon expiration ["Please contact your
provider"]
-f script_name
File name of the script to compile
-i inline_option
Inline option for the shell interpreter i.e: -e
-x comand
eXec command, as a printf format i.e: exec(\\'%s\\',@ARGV);
-l last_option
Last shell option i.e: --
-r Relax security. Make a redistributable binary which executes on
different systems running the same operating system.
-v Verbose compilation
-D Switch on debug exec calls
-T Allow binary to be traceable (using strace, ptrace, truss, etc.)
-C Display license and exit
-A Display abstract and exit
-h Display help and exit
ENVIRONMENT VARIABLES
CC C compiler command [cc]
CFLAGS C compiler flags [none]
EXAMPLES
Compile a script which can be run on other systems with the trace
option enabled:
example% shc-v -r -T -f myscript
BUGS
The maximum size of the script that could be executed once compiled is
limited by the operating system configuration parameter _SC_ARG_MAX
(see sysconf(2))
AUTHOR
Francisco Rosales <frosal@fi.upm.es>
REPORT BUGS TO
the author.
4th Berkeley Distribution Jun 18, 2003 shc(1)
