CODEWITHSUNDEEP
cstring
metalhead696
metalhead696

Reputation: 345

C: Using strtok to parse command line inputs

For a school assignment, I have to make a Unix shell. One of the features that we have to implement is the ability to execute multiple commands from the same line when they are separated by ';'. I'm trying to use strtok to make this happen but for some reason, it only executes the last command (for instance, "ls ; pwd" only executes pwd). Both commands work fine when used individually, but not together. Here's the code involving strtok

const char* s = ";";
char* token = strtok(pinput, s);

        while( token != NULL ) 
        {
            int argc = get_argc(token);
            char** argv = get_argv(argc, token);

            parse(argc, argv);

            token = strtok(NULL, s);
        }
    }

I've tested get_argc, get_argv, and parse a bunch and they both seem to work fine. Is there anything that I'm doing wrong in my use of strtok? Thanks.

Upvotes: 1

Views: 6015

Answers (2)

iammowgli
iammowgli

Reputation: 157

I don't know what your get_argc() and get_argv() are doing ... so here is something that explains usage of strtok for user input from command line. 

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

// Sample command line => a.out 'ls;pwd;ls;pwd'
// Have to use quotes around your input from command line, due to the 
// special character ";" in your input.

int main(int argc, char *argv[])
{
        int iLen = strlen(argv[1]);
        char *sInput = (char *)malloc((iLen+1) * sizeof(char));

        strcpy(sInput, argv[1]);
        printf("String => %s\n", argv[1]); // String => ls;pwd;pwd;pwd

        char *sSeparator = ";";
        char *pToken = strtok(sInput, sSeparator);

        while(1)
        {
                if(pToken == NULL)
                        break;

                printf("Token = %s\n", pToken);

                pToken = strtok(NULL, sSeparator);
        }

        return 0;
}

Upvotes: 1

shruti1810
shruti1810

Reputation: 4037

You can instead take the entire string as input, and then split with ";". As it is school assignment, I would like you to try to code it.

Upvotes: 0

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