.LP
Most of the UNIX utility programs use stdin and stdout for thier I/O and
are therefore appropriate for use as "Commands".
For example, one could use cantata to write a simple "shell script"
to check to see if Joe is executing any processes.
.LP
For this example, you will need two "Command" glyphs and an "ASCII File
Viewer" glyph.  In the first "command" glyph, enter the command as
"ps -aux".  In the second "command" glyph, enter the command as "grep -i joe".
Connect the three glyphs and then execute the network (pipeline).
If there is no user called joe executing a process, the grep routine
will fail giving you an unhappy face.
.sp
.LP
WARNING: If the program that you execute uses stderr, you will get
an unhappy face on the glyph when it is executed.
