$ ); echo $? echoed 0,all other shells echo 2.

[unix-history] / usr / src / bin / sh / alias.h

/*-
* Copyright (c) 1993
*      The Regents of the University of California.  All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* %sccs.include.redist.c%
*
*      @(#)alias.h     8.2 (Berkeley) %G%
*/

#define ALIASINUSE      1

struct alias {
       struct alias *next;
       char *name;
       char *val;
       int flag;
};

struct alias *lookupalias __P((char *, int));
int aliascmd __P((int, char **));
int unaliascmd __P((int, char **));
void rmaliases __P((void));