The gzexe utility allows you to compress executables in place and have them automatically uncompress and execute when you run them (at a penalty in performance). For example if you execute gzexe /bin/cat it will create the following two files:
-r-xr-xr-x 1 root bin 9644 Feb 11 11:16 /bin/cat
-r-xr-xr-x 1 bin bin 24576 Nov 23 13:21 /bin/cat~
/bin/cat~ is the original file and /bin/cat is the self-uncompressing executable file. You can remove /bin/cat~ once you are sure that /bin/cat works properly.
This utility is most useful on systems with very small disks.