argv

fancy-argv0.c

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

int main(int argc, char* argv[]) {
    pid_t pid;


    if (argc > 1) {
        fputs("Execed child with argv[0] ", stdout);
        fputs(argv[0], stdout);
        fputs(" and argv[1] ", stdout);
        fputs(argv[1], stdout);
        fputc('\n', stdout);
        sleep(10);
        return 0;
    }

    pid = fork();
    if (pid) {
        char command_line[80];
        snprintf(command_line, sizeof(command_line), "ps wup %d", pid);
        fputs("Forked parent, running ps\n", stdout);
        system(command_line);
    } else {
        fputs("Forked child, execing self\n", stdout);
        execl(argv[0], "ooga-booga", "child", NULL);
    }
    return 0;
}

invocation.txt

# amitg @ athena in ~ [9:17:56]
% gcc -g -Wall -c fancy-argv0.c

# amitg @ athena in ~ [9:17:58]
% gcc -g -o fancy-argv0 fancy-argv0.o

# amitg @ athena in ~ [9:18:00]
% ./fancy-argv0
Forked parent, running ps
Forked child, execing self
Execed child with argv[0] ooga-booga and argv[1] child
USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
amitg      32659  0.0  0.0   2420   732 pts/5    S+   09:18   0:00 ooga-booga child