data-compression in a pipe

[Dieter Becker]

I am looking for a text-compression program, which works in a pipe
I want to use this in a shell-script like:
    tar cvf - xyz | "*compression*" | rcp xxxx
Do You know a PD-source / program? 
Thanks 
Dieter Becker
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* Dr. med. dipl.-math Dieter Becker          ** Tel.: (0 / +49) 6841 - 16 3046 *
* Medizinische Universitaets- und Poliklinik ** Fax.: (0 / +49) 6841 - 16 3369 *
* Innere Medizin III                         ***********************************
* D - 6650 Homburg / Saar                    ** email:                         *
*                                            ** becker at sbuvax.cs.uni-sb.de     *
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