weird csh thing

[Brandon S. Allbery KB8JRR]

As quoted from <BAGCHI.91Jan6000722 at snarf.eecs.umich.edu> by bagchi at eecs.umich.edu (Ranjan Bagchi):
+---------------
| anyone care to explain??  (I`m in csh)
| $ echo $p
| w | tail +3
| $ $p
| Usage: w [ -hlsuw ] [ user ]
| $ w | tail +3
| benjo    ttyp3    10:13pm           41      4  -sh 
| benjo    ttyp4    10:17pm         3:22      4  -csh 
+---------------

You'll find that sh does the same thing.

The reason is that variables are handled *after* the line is broken into
commands.  Since | is a command separator, it is parsed relatively early.
After sh or csh does command parsing, it expands variables... and since it's
too late to handle |, it's passed literally.  Similarly, < > is (I think)
parsed *but not necessarily executed* before variable substitution.  I also
seem to remember redirecting into the output of a command working under sh but
not under csh....

Shells are *weird* beasties.

++Brandon
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