Fake the process name of an arbitrary command to help distinguish between multiple concurrent instances

maskname.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

void usage(char *name);

int
main(int argc, char *argv[])
{
	char	*rexec;
	char	*nargv[argc-1];
	int		 i;

	if (argc < 3)
		usage(argv[0]);

	nargv[0] = argv[1];
	rexec = argv[2];

	for (i = 1; argv[i+2]; ++i)
	{
		nargv[i] = argv[i+2];
	}
	nargv[i] = '\0';

	exit(execvp(rexec, nargv));
}

void
usage(char *name)
{
	fprintf(stderr,"USAGE: %s mask real [arguments ...]\n", name);
	exit(1);
}