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SamaruX is a Unix-like shell for the CP/M operating system & the Z80 CPU.

It has been developed with MESCC, my Small-C compiler version for CP/M and Z80.

Instead of write separate commands for each task as in real Unix, the shell has some built-in commands.

Of course, it's not at all a new idea (see BusyBox, for example), but I believe this scheme has a lot of advantages in a small environment like CP/M.

For example, we can save some bytes on disk by joining some commands in one file, instead of writing them as separated ones, because we don't have to repeat some shared code in each of them.

Anyway, the last versions of SamaruX support the development of external commands too (some of them are included as examples).

Obviously, SamaruX doesn't have all functionalities of Unix, but it has some nice and useful commands, to work in a Unix-like system, under our beloved CP/M operating system.

Some SamaruX functionalities are:

  • Redirection of stdin and stdout with > and <.
  • Piping with |.
  • Environment with variables $TERM, $USER, etc.
  • Names for directories.
  • Command line history.
  • Profiling for environment customization.
  • Command aliasing.
  • Batch processing with flow control and arguments passing.
  • Complete on-line manual.
  • Prompt customization.
  • Built-in commands: cp, rm, mv, man, cat, more, grep, cd ...
  • External commands: banner, whoami, robots, cal, head, strings ...

This document is not an exhaustive reference of SamaruX, but only an overview, in order to show some of its capabilities. Please, refer to the manual for a complete description.

New in v1.02 / 27 Feb 2015

  • Enhanced command line edition.
  • New environment variables: LINES, COLUMNS, TMPDIR.

New in v2.00 / 09 Apr 2015

  • New built-in commands: date, mem, sort, wc, tee.
  • Improved built-in commands: batch, cat, cd, cpm, ed, env, if, man.
  • New environment variables: HOME, BINDIR, MANPATH.
  • Added support for SamaruX external commands (the game Robots has been included as an example).
  • Text manual included.

New in v2.02 / 22 Ago 2015

  • Enhanced support of SamaruX external commands.
  • New examples of SamaruX external commands: banner, cal, head, whoami, strings.

New in v2.03 / 03 Sep 2015

  • New built-in command: diralias.

SamaruX now has support for named directories.

With the use of diralias, you can reference a directory (a drive and user specification) with a name. IE:

diralias system a0:
diralias temp m0:
diralias mescc a3:

cat mescc:sx.c | more
ls system:*.x
cd temp:

It's a good idea to include the diralias commands in the SamaruX profile.

New in v2.04 / 04 Sep 2015

Executing SamaruX external commands:

Like in previous releases, SamaruX will search the external command files in the directory specified in the environment variable BINDIR:

env BINDIR system:
It this variable does not exists, or it's not valid, SamaruX will search the external command files in the current working directory.

If you prefix the filename with a directory, Samarux will search the external command file there:
mescc:cc myprog
New in this release: You can force SamaruX to search a external command file in the current working directory, if you prefix the filename with the character ':', as in:
Searching manuals with the command man:

Like in previous releases, SamaruX will seach the manual files in the directory specified in the environment variable MANPATH:
env MANPATH manuals:
It this variable does not exists, or it's not valid, SamaruX will search the manual files in the current working directory.

If you prefix the filename with a directory, Samarux will search the manual file there:
man mescc:help stdio
New in this release: You can force SamaruX to search a manual file in the current working directory, if you prefix the filename with the character ':', as in:
man :help stdio

New in v2.05 / 06 Jun 2016

  • New built-in commands: false, head, shift, tail, true, tty, whoami.

Some built-in commands can be compiled as external ones.

Compile SamaruX with SX_MINIMAL for a minimal number of built-in commands. Then execute make_all_ext2 to build the excluded built-in commands as external.

Execution modes

There are two execution modes:

  • CP/M mode: The SamaruX shell will execute only a command and will return to CP/M.
  • Interactive mode: The SamaruX shell will read and execute your commands from the keyboard, until you return to CP/M.

CP/M mode example:

A>sx echo Hello world!
Hello world!


Interactive mode example:

Samarux v1.00 / 29 Dec 2014 - (c) FloppySoftware, Spain

CP/M version 2.2

28 built-in commands

Hi FloppySoftware welcome to Samarux!

[FloppySoftware at B00:] $ env
TERM = vt52
USER = FloppySoftware
PROMPT = [%u at %w] %$

[FloppySoftware at B00:] $ exit



With profiling, you can customize your SamaruX environment.

Its use it's not compulsory, but highly recommended (and useful).

There are two files for profiling::

  • profile.sx: For the CP/M mode.
  • profcpm.sx: For the interactive mode.

An example of profiling in interactive mode:

# -------------------------- #
# -------------------------- #
env TERM vt52
env USER FloppySoftware
env PROMPT [%u at %w] %$
alias h history 0
alias logout exit
echo Hi $USER welcome to Samarux!

Piping and redirection

With SamaruX, you can enter useful command lines like:

  • cat letter.txt | more
  • grep 'Gary Kildall' cpm.txt article.doc news.txt > refs.txt
  • ls -l *.h *.c > cfiles.txt
  • man cat | more

Command line

You can separate commands in the same line with the semicolon (;):

man cp > cp.txt ; clear ; cat cp.txt | more

You can include environment variables in your command lines:

env NAME Julius ; echo My name is $NAME

An argument can contain spaces if it is surrounded by single quotes ('):

env NAME 'Julius Smith' ; echo My name is $NAME

SamaruX has a command line history facility.

To see the history, just type:


And the history command will reply something like:

[FloppySoftware at B00:] $ history
0: cat manual.doc | more
1: ed letter.txt
2: ls *.c
3: man cat

To select a history command entry, just type its number:

history 2

And the shell will present a command line, ready to be edited and / or executed:

[FloppySoftware at B00:] $ ls *.c

Executing CP/M commands

You can execute CP/M commands by using the cpm command:

cpm PIP A:=M:*.COM

You will return to SamaruX, once the CP/M command had finished its work.


You can make aliases for your most frequently used commands:

alias dirall ls -f

Then, you can enter the defined alias as a single word:


Small text editor

SamaruX has the ed command, a very humble text editor, but very useful to create and edit small text files in a fast way.

[FloppySoftware at B00:] $ ed profile.sx
File :  profile.sx
Lines:  14/48
ed> print
    0: # -------------------------- #
    2: # -------------------------- #
    3: # env HOME A00:
    4: env TERM vt52
    5: # env TEMP M00:
    6: env USER FloppySoftware
    7: env PROMPT [%u at %w] %$
    8: #
    9: alias h history 0
   10: alias logout exit
   11: #
   12: echo Hi $USER welcome to Samarux!
   13: echo
ed> edit 8
    8: # This is a comment


SamaruX has a built-in command named man, to offer on-line help about commands an other topics.

The help contents is stored in the samarux.man file.

As this file is an ordinary text file with a simple structure, you can even add or modify topics.

To see the available topics, just type:

man | more

To read about a topic in particular, say cat, just type:

man cat | more

In addition to this, SamaruX has a built-in command named builtin, that prints the name of all available built-in commands. Just type:


Batch processing and flow control

With the batch command, you can process files with commands as if they were typed on the keyboard.

Some other SamaruX commands will help you with flow control in batch processing:

  • if
  • goto
  • read
  • exit

An example:

# ----------- #
# ----------- #
echo Test Script
echo ===========
# Menu:
echo 1 : Option One
echo 2 : Option Two
echo 0 : Exit
echo -n Your choice:
read OP
if $OP eq 1 goto One
if $OP eq 2 goto Two
if $OP eq 0 goto Exit
echo Bad choice, try again.
goto Menu
# One:
echo Your choice was Option One.
goto Menu
# Two:
echo Your choice was Option Two.
goto Menu
# Exit:
env OP

You can include arguments in batch processing.

If you have a file named write.sx with this contents:

echo $1 $2 $3

And you type:

batch write.sx How are you?

The system will reply with:

How are you?


SamaruX screenshot running under CP/M Plus