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Special Read Only Variables

The C shell maintains a list of special variables that can be read by the user, but not written to or changed explicitly. One of these was examined in the section on parameters, $argv[n] which returned the value of the nth parameter of the shell command line. Table 4.4 contains all of the special readonly variables use in the C shell:

Table 4.4:  Special read-only variables used in the C shell.

For example, to check whether noclobber is set, one could enter the following:

% echo $?noclobber

which would indicate that noclobber is indeed set. The usefulness of these variables will become apparent in the shell programming sections.

Douglas M Gingrich
Mon Apr 27 15:25:49 MDT 1998