Thread: Handling multiple input files from command line

Hi all,

I need some advise on how to handle multiple possibilities in the way of files from the command line. I'm not asking how to use command-line arguments, but how best to handle possible parameters.

For example, I have a command-line tool that will accept the following file possibilities:

singleFile.fm
*.fm
---------------
single.bk
single.book
single.fmb
*.bk
*.book
*.fmb
---------------
*.*

I'm looking for some advice/ideas on how to handle such a wide range of file input possibilities. As you can see, it can be a single file, all files of a particular extension, or all files within the directory.

Your thoughts appreciated!

You know that shell does wildcard expansion? ("cmd /?" or "man bash") If you want to do it yourself, you can define your own wildcards/patterns as you like because you're gonna have to scan for every file/dir and do matching yourself.

man scandir

Code:

/* print files in current directory in reverse order */
#include <dirent.h>
main(){
    struct dirent **namelist;
    int n;
    n = scandir(".", &namelist, 0, alphasort);
    if (n < 0)
        perror("scandir");
    else {
        while(n--) {
            printf("&#37;s\n", namelist[n]->d_name);
            free(namelist[n]);
        }
        free(namelist);
    }
}

(Not in POSIX.1-2001, but alphasort() and scandir() are under consideration for a future revision to POSIX.1. )

Sorry, I should have mentioned that the app I'm writing is for Windoze machines.

Ok. So did you read any of rasta's response? This is still going to involve talking to the operating system and doing some scanning.

Thanks Mole and Rasta. I appreciate your responses.

Thanks especially to you Rasta. I didn't know the shell would take care of the expansion for you. I read in a number of places on the internet that the application was responsible for handling wildcard expansion on Windoze machines. I was thinking I would have to deal w/ all possible nuances myself. Off to test this out. . .

After a quick test, it looks like the cmd shell in Windoze does not expand wildcards for you. What the program gets is exactly what you type in.

Originally Posted by cnfwriter

After a quick test, it looks like the cmd shell in Windoze does not expand wildcards for you. What the program gets is exactly what you type in.

Code:

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

int main(int argc, char* argv[]) {
    printf("Argc is: %d\n", argc);
    printf("Argv are: ");
    for (int i = 0; i < argc; i++) {
        printf("%s ", argv[i]);
        if (!((i+1)%5)) {
            printf("\n");
        }
    }
    return 0;
}

Code:

C:\DOCUME~1\Andrew\Desktop>temp c*
Argc is: 8
Argv are: temp casting Chapter04_Code Chapter09_Code check1.txt
check2.txt CIS460_Syllabus[1].doc crayon

You do have to (gasp!) type the command yourself, though.

Thanks tabstop and matsp.

Yes, my test program is similar to yours Tabstop, but doesn't yield the same results. Thanks matsp for clearing things up. You are right. I am compiling w/ Visual Studio.

Is gcc adding some kind of wildcard expansion routines behind the scenes whenever you compile? It could be worth compiling things in gcc just for the benefit of not having to write a bunch of routines to deal w/ wildcard expansion.

I read that there are already some libraries out there for VS to do this, but I haven't tripped across any yet.

I hadn't realized there would be a difference. A little bit of searching gives this Microsoft page, and who knows whether that helps.

I had to wait until I got into the office this morning to try it out in Visual Studio, but the solution does indeed work as mats mentions.

Thank you very much for finding this solution Tabstop!! And thanks to you again mats for your insightful help as well.