Hello to all,

I am receiving a bus error when I run the following code:

Code:
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>

typedef struct { char *name ; char *data ; int length ; int type ; } sequence ;

sequence loadedSequences[1000] ;

int nSequences = 0 ;
    
int main()
    {
        char buffer[1000] ;        
        char *command ;
        char *filename, *list_num ;
        
        
        for(;;)
            {
                printf("SeqTool> ") ;
                fpurge(stdin) ;
                
                fgets(buffer, 1000, stdin) ;
                fpurge(stdin) ;
                
                // Eliminating the newline character
                char *p = strchr(buffer, '\n') ;
                if (p) 
                    {
                        *p = '\0' ; 
                    } 
                                          
                command = strtok( buffer, " \t\n" ) ; 
                
////////////////// Load sequence in FASTA format //////////////////////////
                
                if( (strcmp ( command, "read" )) == 0 )
                    {
                        char *fileName ;
                        fileName = strtok(NULL, " \t\n" ) ;
                        FILE *input = fopen(filename, "r") ;
                        fgets( buffer, 1000, input) ;
                        char *seqName ;
                        seqName = &buffer[1] ;   // After the > in FASTA format  
                        
                        loadedSequences[nSequences].name = 
                            (char *) malloc( ( strlen(seqName) + 1 ) * sizeof( char ) ) ;
                            
                        strcpy( loadedSequences[nSequences].name , seqName ) ;
                        
                        ++nSequences ;
               
                    }
What I am trying to do is read in from a standardized format (FASTA) and collect the data so that I can manipulate it later if needed. The syntax for the command should be:

SeqTool> read <filename>

Any help would be great.